Would a time-travelling blockchain destroy a cryptocurrency?

Question

The story

So Bob, the multi-billionaire, is a wealthy person today but in a not so far away future he will lose quite a chunk of his wealth and become just an ordinary millionaire.

Future Bob is no longer building diamond studded swimming pools and he actually had to melt a few of his solid gold Humvees. He is especially upset because he knows that his great loss was due to his long-life investments in international banks' products. His loss is related due to the following sequence of (future) events:

1. the greatest global economic crisis in history hit the world in 2017;
2. there was a sequential collapse of several major currencies;
3. people panicked and started withdrawing most of their money from banks or buying what valuable things they could afford;
4. most banks in order to cope with the sudden withdrawal, started to restrict withdrawals (some completely refusing) and, with governments agreements, they were taxing heavily any transferences or larger payments;
5. the value of precious metals and jewels rose up and most wealthy people who could still afford them, invested heavily in purchasing everything that could be found on the market and placing them in banks' vaults (this is when Bob started melting his gold Humvees);
6. cryptocurrencies saw a steady rise in the beginning of the crisis and since there was no viable way to track most of them and tax payments/transferences, they became a plague for bankers, governments and wealthy people who traded little and kept their precious stuff in vaults (Bob for a very long time refused to buy any crypto-coins);
7. over the years, precious metals value started declining and governments tried to contain cryptocurrencies by request(forc)ing internet providers to turn off their services in order to block their nodes; once alternative internet providers (altnets) started mushrooming everywhere, large EMPs were being systematically detonated by governments in an attempt to disable general electronic devices;
8. cheap handheld manual and solar powered EMP-proof devices were being illegally and randomly dumped in the mailboxes and on the doorsteps of middle and lower class citizens in order to allow them to trade without money and keeping alive crypto-markets and non-governmental industries.

Watching his wealth diminishing everyday and no profitable business to run, Bob focused on one of his old research hobbies based on his favourite time travelling trilogy. With the help of a few kidnapped mad scientists, he managed to produce a piece of hardware that was able to connect to the internet of a previous point in the past. Initially he thought of warning his past self (in our current timeline) to invest and transfer his wealth into cryptocurrencies, but one mad scientist let slip the unthinkable:

• I wonder what would happen if today's altnets blockchains connected to that past internet and synchronized... That would reveal all the trades that were made up until now to them, wouldn't it?

Bob thought better, and he started liking this idea much better: not only he would be able to render useless these things that were harming his precious "real" wealth, he would be considered a hero amongst governments all over the world and history would be rewritten by himself alone! He would also be finally able to fulfil his dream of replacing the sand of his island with diamonds and rubies.

The question

If Bob succeeds in synchronizing future blockchains (containing millions of transactions in the future) into our timeline's cryptocurrencies, what does he really accomplish with that?

Would it really force them to shut down or would it backfire and make them stronger by providing knowledge of the future and opportunities of trade?

^{Notes: I previously asked a smaller, summarized but broader question in here that I did not have the time to detail it in a Worldbuilding perspective (it is now closed). In Bitcoin.SE however, I asked about the technical details of this event's possibility and I must say, I am pleased with the detailed answers, and they may help answering this question.}

Answer 1

I see several points in this story which wouldn't really be able to happen, but I give a try to answer rolling with the setup:

Please note, these things clash with real world concepts!
"...what does he really accomplish with that?" Speaking about succesfully making connection between "old-time" and "new-time" internet, information exchange begins. It will create bigger confusion in "old-time", because they are unaware of what has hit them, slowly they will cope with, and data will reach back and forth. As long as "old-time" has effect on "new-time", so long it will prove to be useful. Loosing integrity will make information invalid, and so the connection will become irrelevant on the track of exploiting foresight advantage. Eventually alternative world communication will develop, and both sides will find benefits in having a similar world on the other end. It can span to parallel researching, gray business test sites, these come up for me at first. If Bob has good sense of business (which is not seem to be the case), he can facilitate these possibilities to make good riches and act as an option to have a river of rubies at his weekend island.

"Would it really force them to shut down or would it backfire and make them stronger by providing knowledge of the future and opportunities of trade?"
Depends on you. The concept is so far from real world, bending to your favor will not cause problem.
A) If the parallel existence has close integrity, future will need to manage past derails, and past will rely on future informations. Most commonly I think past will realize a control function above future, and as long as future is not getting fatally manipulated, past will abuse this power. So either future will sieze the altnet connections to prevent harmful events generated by past, or there will be strict regulations to use.
B) If the parallel existence has no integrity, it will be a matter of collective will appearing on the altnets. If many villains turn to altnet to benefit, altnet will have that effect for past, and same from past to future.

I hope this will prove to be a feasible answer for the setup and your question.