Not so bad. I use gmail as a backup for some accounts in case something happens to my VPS or domain, and my Amazon account is still linked to it out of laziness, but otherwise I never use it.
Oh. Except that I have an Android phone, and that’s linked to my gmail, although I don’t use any Google apps or services beyond Play. So I suppose my phone would stop working. Everything’s backed up, though, so maybe it’d be a good thing; maybe it’d motivate me to pull the trigger on a Light Phone. I kinda want a Minimal Phone because my F&F uses Jami, but that’d still be an Android phone, so it wouldn’t work either.
I haven’t tried it yet, and I haven’t had a reason to look into it. My experience with Fi was that you pay $10 per Gb - it didn’t come out of your normal bank - and per-minute charges. When I was traveling, I used my company phone, or if on vacation, purely data with heavy up front-caching as much as I could at the hotel. I really don’t like surprise bill sizes.
But to be honest, I haven’t tried Mint internationally, so I can’t say.