[fortytw2]

SHA-2 is still dandy - If I understand correctly SHA-3 is in an entirely different family of cryptographic hash functions, so that if/when a problem is discovered with SHA-2 there's another standard approved and ready to go - but that doesn't mean SHA-3 can't be used now.

[logicrime]

I gotcha, that makes sense to do it that way, such that if the foundation of SHA-2 is compromised, SHA-3 can be deployed safely where it's needed.