Walls

As a wall certainly not. One of the great benefitsit would be decently strong if you put a barrier of walls is thatsome kind behind it hides your movements from the enemyyou could easily make it similar to a normal wall. Also Although unbreakable doesn't mean it cannot be either dug under or scaled so it wouldn't make much of a difference.

Armor

As armor there are a few interesting thing you could do with this. As someone mentioned before, a see through helm would be a great tool. Honestly though why stop there? a see through shield would be a great tool as well. The main problem would be that the user of the armor could still be killed. there would have to be breaks in the armor to allow for mobility and the fact that it dents means that a blunt weapon could be an effective means of countering this armor to some degree. having unbreakable armor like this could mean that certain tactics like the phalanx (basically a wall of spears to counter cavalry and charging armies.) would be much less effective.

weapons

Having see through spike in shallow water is a good idea but to expand further on that idea previously mentioned by Henry it might be an effective means of guarding coastal cities from naval invasions. Weapons made from this materiel would probably be as good as any other metal they had at their time considering how it bends. It may be a better option to stick with steel swords.

All in all it is a strong defensive choice but not necessarily a strong offensive choice.