Seems mostly useless. If you encase yourself in the metal, you can't attack from within unless you use your hands.. If you use it as a weapon, the only advantage is if it finds some advantage to go through you--I can't imagine a simple weapon where you could make that matter by enough to make a difference.

I suppose the BEST use is as a door in a large wall--Nope, you'd have to get naked to run through.

Internal armor with various external mount points is interesting but would be heavy and it would still hurt you a lot to get hit (and you'd tend to bleed) unless it was slightly outside your skin (in which case, how is it better than normal armor?) All the disadvantages of plate (Weight) and more (Skin is still vulnerable if visible). Plus if it took a hit it would distribute the shock to the mount points instead of across your whole body causing do more damage to you because of the concentration than external mail.

It wouldn't even make a good solid cube vault, although you could get into it (naked) you couldn't add or remove anything.

Sorry, can't come up with a single realistic advantage.

If we had todays technology though I'd make a backpack a motor and a couple sets of counter-rotating blades that went through my midsection. Not only could nobody get near me without a gun, tilting the blades might let me fly :)

OH! Bullets! It would be great if someone who stole your gun couldn't shoot you. Of course you said melee weapon :(

Seems mostly useless.

If you encase yourself in a metal bunker, you can't attack from within unless you use your hands..

If you use it as a weapon, the only advantage is if it finds some advantage to go through you--I can't imagine a simple weapon where you could make that matter by enough to make a difference.

A door in a large wall: Nope, you'd have to get naked to run through.

Internal armor with various external mount points is interesting but would be heavy and it would still hurt you a lot to get hit (and you'd tend to bleed) unless it was slightly outside your skin (in which case, how is it better than normal armor?) All the disadvantages of plate (Weight) and more (Skin is still vulnerable if visible). Plus if it took a hit it would distribute the shock to the mount points instead of across the whole side of your body causing do more damage to you because of the concentration than external mail.

It wouldn't even make a good solid cube vault, although you could get into it (naked) you couldn't add or remove anything.

Sorry, can't come up with a single realistic advantage.

Oh, got it! you never said we didn't have new technology: It's not an existing weapon but I'd make a backpack with a motor and a couple large (7' radius?) counter-rotating quad blades that went through my midsection. Not only could nobody get near me without a gun, tilting the blades might let me fly :)

Oh and if you hadn't said it had to be melee weapon I'd say bullets would be a good answer.

Also, smuggling entire items like guns (as long as nobody x-rays you)