I think it should support desktop computers too, but yes it's not really unreasonable in this day and age to expect working age people to have access to a smartphone or desktop. You need lots of other things to get a job anyway e.g. a bank account, postal address. Those are actually significantly worse requirements.
"Think of the OAPs" is why it took literally decades to get online NHS appointments.
I hope this encourages the remaining Ruby devs to move to languages that aren't quite so awful to work with. Even Python is significantly better at this point, now that
uvhas mostly solved the tooling disaster.