Mass-users need to have fail-safe onboarding and a fully working experience.
I know this argument's been lost, but by (effectively) losing compatibility with classic email most of my contacts haven't moved to secure, private comms but to Facebook Messenger. At least mail with autocrypt was private when both participants wanted it to be.
By moving away from email, Delta Chat has become just another app that my friends won't install because none of their other friends use it.