Security should really be a thing of great importance and 2fa seem to me like the latest way to add an extra level of security to accounts online. I even know of projects who make 2fa a compulsory action for its members during signup.
Really great suggestion. They should be keep google authentication or something email verification. Its can keep safe to investors from hackers/scammers.
Between Google authenticator and email, I think I will rather vote for 2fa service offered by Google rather than email. But a combination of both will be great though
Google authenticator is better and more preferably than email, as the security breach of emails has been on the high side of late, especially since the bloom of ICOs, hackers have gone haywire, trying to hack any account they can set their eyes on, so anything that can guarantee high level of security should be encouraged
Google authenticator is my favourite to secure the account, but if they decide to verify with email I'm fine with it too.