>You stated that any SMTP can be used for deltachat, so non chatmail servers have to be taken into account as well
And this continues to be the cruc of my argument. Everyone shilling DeltaChat does so with the disingenuous argument that "you can just use your existing email!"---which isn't really honest. There are major providers where it doesn't work. Assuming that does work, the recommended "best practice" is to have a separate email address entirely to use with DeltaChat vs. your primary, normal email address. And then, thereafter, to address all the performance issues associated with [*squints*]……trying to use email as an instant messenger platform……, and to utilize all the marketed features supposedly available immediately out of the box, the recommendations and solutions are to spin up, or have an account on, a specialized email stack.
By the time you do all of this one could otherwise be using an instant messaging protocol made for instant messaging.
Ultimately, the "sales pitch" is, dare I say, intentionally dishonest. @feld