No, your attendees do not need to create an account with Corsizio or log in for any reason. When you create an event (class, course, workshop, etc.) and have them register, the student is solely registering for that single event, and not to Corsizio or any of its services as a whole.
This keeps the registration process to your events simple, most efficient, secure, and streamlined, by not requiring potential attendees to register directly to Corsizio or create an account.
Attendees who regularly register to your events can easily pre-fill registration fields by having the auto-complete feature of their web browser do it for them.