@JayKemp
Canvas has started requiring an email address for all things done through the web UI. I can still create user accounts through a SIS import and bypass the email requirement, but then I cannot edit them later through the web UI.
We used to create logins through Canvas for certain students who did not have an institutional email address (their department didn't put their users into our SIS). When they would come back and say "Oops, we misspelled the name, can you fix it?" I would have to do another SIS import to make any changes. Thankfully, they have started adding email addresses now so we can manage them better with the web interface. Note that those students still don't use their email addresses for email, but they use it to log into Canvas using our single sign-on solution.