Could be if there are less steps to create an account more people would do that. This may be a new feature request or dev topic to figure out if that is possible or not.
There is a default setting allowing username to be changed within first three days of new account being created. Maybe you could have a random name generator create temporary name for new accounts which can be changed.
There is the staged user account feature which creates a partial account based on only e-mail if someone sends in e-mail to discourse site, don’t know if that would work for your use-case.