A scheduled appointment should be able to start a conference.
The disconnect between calendar events and the conference tool didnt make sense to me. It occurred to me that you can create an appointment and get students to sign up to it, but the appointment never went any further and did not integrate at all with the conference tool.
The scheduled appointment would have an option to run the event using Conferences, this can be toggled on or off to indicate the appointment will run the Conference tool using the Appointment information or as a normal appointment for other use. Default would be toggled off.
If you used the appointment tool to create an event for students to sign up to, the data would then have to transferred somehow from the appointment to the conference. This is a manual intervention that runs the risk of missing someone out.
An elegant solution to this is for the appointment to launch the conference and invite the students who signed up. Much easier.