I still think there's a data sovereignty argument against the move we're discussing on this thread. That it's just friction makes the move less bad, but I think it's still bad.
The whole point of computing is being able to set up seamless interfaces for doing things you want done. It might be more secure that way, sure, but past some point security is opposite to utility. For me, it's just another reason I'm happy with moving my primary mail to FastMail on my own domain.
2) Even with a mechanism like the above, part of the issue with communication/social data like Gmail is that you can’t control your own privacy perimeter, because the other party could inadvertently leak your data through another app they connect
"Gmail app developers have been reading your emails" (The Verge)
"Google admits it lets hundreds of other companies access your Gmail inbox" (Telegraph)
"Google's 'Dirty Secret' Allows Third Party Apps To Read Gmail Messages" (TechTimes)
And all those articles were accompanied by appropriate ravenous Google bashing on this very site.
What exactly do you expect a company to do if the developers of HN and the "educated" tech media attacks it for having an open API?
In snail mail, a sent letter becomes the property of the recipient, and the recipient can do whatever he wants with it. Why should email be different? We're not talking about a static "profile" like Facebook has, but individual messages.