I'm a bit iffy on the idea. I don't like the sound of taking a perfectly happy sharp knife and intentionally bending and prying with it (crowbar) pounding it into rock (Pitons, Pick) or dirt (Trowel). I'm certainly not quite getting how you would make spiked armor or shields, either. I'm under the impression that Spiked armor and shields are useful because their spikes do not move, as Kunai on ropes would. Kunai, being throwing weapons, are balanced for throwing. I can see some of these things being used, but as an improvised weapon at best.

I admit that it's no Kunai, but I have a pocket knife that's badly bent because someone tried to pry something open with the knife blade. I can't see how anyone would expect to actually use it in any of these ways.

Just as an aside, do you watch a lot of Naruto?