Well PGP never get successful and leak a lot of data even if used so it's not a solution. Email wasn't designed for privacy nor security. "Extensions" like that doesn't solve that.Could be what the online reviews say:
No PGP support.
But their blog outlines the reasons, Security measures to look out for in a secure email service.
I use Posteo for years and never has any problems. You get a info if payment is needed and if it was successful. Also you can see all billing stuff in account.I would not mind paying for one like postdeo, but I do not want to end up without a service, because of a failed payment, thus I prefer a free one.
None of these paying services would disable the account without any warning.
I prefer paying over free mail as the free are too slow (like Disroot / Dismail) and somehow the server need to be payed - with money in the end.