And use it only for important things that won't be delivered if you don't send them from Google.

Receive only (e.g. account signup)? Use your own account. Not important anyway? Use your own account. Your recipient needs the email more than you? Use your own account. None of the above? Use a mainstream provider for that email only.

But this is why I'm using Amazon's SES for sending my very low volume emails now. It's never been blocked, if they ever start causing me grief I can switch to a new email relay service in a matter of minutes if necessary.

Not really, I don't send many emails these days but find the ability to filter and run automations on emails coming into my server very useful.

Not to mention I use a separate email per service so I can tell if there's a data breach (usually end up seeing an uptick in spam).

*Edit: Not to mention I can pay for a relay service other than Amazon SES without using Google's services, and for significantly less.