Andy Yen's values are incompatible with Proton's mission. He advocates for poor security practices, supports fascists, and he verbally abuses his subordinates. As such, I can no longer in good conscience continue to financially support a company with such terrible leadership.
Unfortunately for me, my subscription just renewed last month on a multi year plan, but it does give me time to browse for and experiment with alternatives.
If you're able, I encourage you to do the same and cite Andy Yen as the driving factor for your decision. We can't let these tech bro fascists destroy what little semblance of privacy we have left.
I didn't mention self hosting nor do I think it's necessary, unless you consider any service running in your desktop as "self hosting".
People need/want/are used to active sync. For that one either needs a true self-hosted solution and/or a service that requires opening port(s) on the firewall/router, which most people either have no idea how to do or can't due to ISP lockdown. Self-hosting can very quickly turn into a 2nd job and not everyone wants that. Or they have no required techical knowledge and no desire or time to learn. Plus, you still have to set up proper backups, even if the service is just running on your desktop. Unless, of course, you're fine with a single point of failure.
On the topic of mail hosting, as someone who works in IT and self-hosts a whole stack of things: I do not ever want to self-host my email. Personally, I was considering just getting another domain for email and switching backend services as needed, but I liked the package Proton offered, so I chose that instead. I might need to rethink that domain option, but at this rate, soon no backend service will be safe from fascists and/or AI.
It is if you want to access it from anywhere on any device. I know SyncThing makes that a lot easier, but not exactly a set and forget kind of thing.