I think it is attack-driven. Most bitcoin wallets/exchanges have 2FA/U2F because...

csomar on July 24, 2017 | parent | context | favorite | on: Soft U2F: A software-based U2F authenticator for m...

I think it is attack-driven. Most bitcoin wallets/exchanges have 2FA/U2F because it is a must given the value at stake. If you are running a forum board, you probably don't care much neither are your users going to bother.