Yes, that’s the way it’s intended to work. That’s not much of a barrier for most users. The issue you need to be aware of is that if the email address is not marked as verified on WordPress, Discourse will not match WordPress users to Discourse users based on their email address the first time they login to Discourse via DiscourseConnect. As long as you figure out how to mark the email addresses of your imported users as verified, that won’t cause an issue. If you don’t mark them as verified, it’s going to be a hassle to sort things out.
If enabled, they prevent users from changing their username or email address on Discourse.