Autopay is simple to set up with any hosting provider. If you're in a financial place where the $5/mo and $10/yr payments might bounce... yeah, probably don't pay for email.
As far as the social engineering goes, personally I gladly take that risk in order to bring my email firmly into my control. If I'm going to lose access to my email, I want it to be because I did something stupid, not because an algorithm flagged my account and Google has no humans I can appeal to.
The long tail of acquaintances isn't bad either: just forward emails from Gmail to your new address. If you lose access to the Gmail account at some point, you'd have lost everything anyway, so this arrangement would be strictly better.
I'm not fully confident that I'll never cancel a credit card that pays annual subscription. Generally it's fine because alert email would come on my inbox, but it's email infrastructure so I need extra attention.
I’m not big on PayPal but I have some domain names set up for recurring PayPal payments (with cc as a backup) because PayPal is insidious with regards to how far they go to fund your account (charging multiple cards, goopy your bank account, sending you letters for debt collection, etc) which, for most things, would be exactly the opposite of what I want but for domain names it’s a huge burden lifted.
As far as the social engineering goes, personally I gladly take that risk in order to bring my email firmly into my control. If I'm going to lose access to my email, I want it to be because I did something stupid, not because an algorithm flagged my account and Google has no humans I can appeal to.
The long tail of acquaintances isn't bad either: just forward emails from Gmail to your new address. If you lose access to the Gmail account at some point, you'd have lost everything anyway, so this arrangement would be strictly better.