no, we don't have 20 options available. we also need to talk to people who don't understand the problem and can't be persuaded to use one of those other options.

there is a difference between enabling phonenumbers as an ID vs requiring them.

signal could easily support both. (i read somewhere that they plan to support alternatives to phone numbers in the future, just haven't made it a priority. well, i'll wait. edit: actually it's mentioned here: https://news.ycombinator.com/item?id=23435050 )