> So this power does not allow to get back a buried armor if we use the bury thing, but just allow us to recharge this card in the reset hand step?
Yes, that power on the card allows you to recharge it back to your deck. The other benefit to armor proficiency, as you've mentioned, is that you can often bury cards to absorb damage instead of having to permanently banish it from your deck. Those two powers aren't related.
> Maybe other use would be if you have two armor, and other useful cards, and too many cards in hand, to recharge an armor instead of discarding something?
Yup! While it is occasionally a useful trick for some characters, with armor-heavy decks like Valeros or Seelah it is really helpful to "clean up" your hand if it has armors you know you won't need.
It sounds like you got the hang of it. Good luck!