I had the same user experience. The volleyball team of my daughter (13 years and younger!) wanted to initiate a whatsapp group. I said no but offered to install a DC-group instead because they had a email list. In principle the interoperability to email lists would be good enough, but these annoying “features” pcrocett describes leads to exact the way he described: I got very fast emails: Pleas take me out of this list. - Before it could be established as a delta-Chat group.
A hint of mine: Is it possible to integrate the How-To with IMAP-Providers like gmail into installations-procedure? Nowadays user are not able to search. If something doesn’t work out of the box, they use another program (mostly whatsapp, that they use anyway).
Just my 2 cts
Martin