I haven’t tried setting up autocrypt. I use the mutt email client, which theoretically also supports it, but there also seem drawbacks to using autocrypt. One reason for me to not use it is certainly that, even though I usually use mutt to check my mails, I want to have the option to do everything in webmail as well. I use Protonmail and their web interface does not support autocrypt (this applies to many other providers as well).
The simplest approach for me is to do the manual key exchange as outlined in this thread (mentioned in my initial post):
Whether autocrypt is generally a good approach for key exchange or not is one discussion, but regardless of that I think that users should at least have the option to perform manual key exchanges. After all the choice of building Delta Chat on top of the email protocol is interoperability (if I understand it correctly). In line with this goal it would thus only make sense to not restrict encrypted email transmission to those who follow a small subset of the available standards for key exchange (i.e. those with access to autocrypt compatible clients).