i would never bother with anything that i consider to be highly secure over any clearnet service. but for keeping advertisers out of my messages or just run of the mill dragnets, or spot-censorship (like how facebook or others forbid certain links), i think deltachat is a really reasonable solution.

but to this point:

, it is inadvisable for privacy to keep data (even in an encrypted form) on a server post delivery.

deltachat has an option to delete server-side.