Deltachat safe, Avantage and disadvantage

Hi. Other protocols are too complicated. Delta is simple. Can i trust Deltachat? And i guess i can not send mail with protonmail. Good days

Can I use Deltachat as storage?

And if I communicate with a protonmail user, will the encryptions continue mutually?

depends on your threat model and what you are scared of.

Not really, unless you have a email provider with much storage space, but I wouldn’t use DC for that.

I don’t know if proton mail supports autocrypt, I would guess no.