Right, more chaos.
Discussion
No, it's a good thing. The @ notation was never meant to be used just by email, email was just the protocol that was more successful. It's time to change that. Also, email is horribly bad, centralized, awful, no one should even be using it. We can't just let them win.
About Gmail, we can probably easily implement something like this: https://www.onebigfluke.com/2013/06/bootstrapping-webfinger-with-webfist.html
And it wouldn't be disruptive to NIP-05 at all as we would hardcode just the top 5 big email providers (I don't even know if there are this many).
I knew it would end this way, capture the @ haha
Okay!