@debby @monocles @Stuxhost well, @delta / #deltaChat is not using #XMPP+#OMEMO (unlike #monoclesChat & #gajim) but #PGP/MIME on regular #eMail, which makes it way easier to setup in organizations as "nit yet another server needed" and also easier to comply with mandatory #archival laws in #business use-cases.
#Session & #Signal, like #Telegram & #WhatsApp, do not have their #backend opensourced nor allow #SelfHosting and demand #PII like #PhoneNumbers for registration if not useage for no valid reason. Plus they are not just able but obviously willing to snitch on their users (something neither DeltaChat nor monocles chat demand or even can as both do 100% #SelfCustody of all the keys!)
As for #sustainability, monocles is financed by #subscribers (they charge like €2 p.m. for mail & chat) and they can be paid completely anonymously (#Monero & #CashByMail!), whereas #Signal is a #MoneyBurningParty which engages in #Shitcoin-#Scams (see #MobileCoin!) for no valid reason…