Email is still being sent as plain text. Encryption is possible even if you're using someone else's server.

Your deliverability is reliant upon other people's good will. Those people have no idea who Joe Sixpack in Idaho is, and have no reason to extend goodwill. Your deliverability is also subject to wingnuts using a variety of good and not so good blocklists. You may find your time is better spent doing work rather than working around various weird blocklist delisting policies.

Hosting your own email does nothing to prevent traffic analysis.

The only thing it does is to stop your email being held in a big bunch at an email providers servers, but you can do that by wiping it from their servers and holding a local store. (tl;dr use a commercial email provider but keep your email on your machines not theirs; encrypt everything before sending it; consider using tor if you want anonymity.)