Other than the awesome “backup email address(es)” idea I thought what really triggered me to want more than 1 email to begin with. Well, I have many different emails… But oauth works mostly with my main one.
I wanted to use oauth to login, but display a different email on my profile.
So, maybe a better idea (for my original intent) would be a “profile email for public display” field, which would still need to be validated as Jeff suggested (well, not needed, but better if we do). This does not exclude the “backup email list” idea, it’s just a different one. 
Maybe I should try to go and cluelessly attempt to implement it myself and make a pull request… 
Should I?