I find it works very well using the bridge on my Manjaro desktop, and was fine on Debian before that.
I'm very happy with the Bridge integrated with Neomutt on Fedora Linux.
I think Protonmail started with a privacy-focused business case (for which E2EE is a key feature), but is now expanding into the broader pool of people who want to pay for an ad-free, no-data-scanning email, but are not concerned about targeted spying and prefer the simplicity of a convenient setup. For that crowd, IMAP would make more sense. My 2c.