Imagine you are far into the adventure path and the day comes your character actually dies because you didn't bother to 'clutter' your hand with armor (or recharged it). What are you going to do? I can only see two options:
1. You will cheat and replay a scenario pretending nothing really happened.
2. You will start new character and re-evaluate your view of armor.
Characters are meant to be persistent. The more you play him/her the more you want to keep him/her alive. I will gladly clutter my hand with one armor piece to ensure I am not going to 'waste' many hours of gameplay.
If you are playing just a single scenario armor might not be the best card you can get, but in a long run it can be the most important thing in your deck.