#1 It's volatile indeed, the important part is, that it's volatile to the upside, given enough time, whereas [a] Fiat ['s supply] is designed to be inflated into obscurity, and thus, worthlessness, given enough time.

#2 Regulate what? Self Custody.

#3 Bitcoin not being "backed" by something isn't a flaw, it's a feature; Moreover, it'll be the very thing that'll be used to "back" others.

Besides, It's backed by the consensus rules and hash rate.