Why does enrollment open and close?
A time-sensitive enrollment period makes a few things possible that would otherwise be very tricky to pull off.
With every enrollment, things get refined, changed, and ultimately improved. Whether it's schedules, additional content, or really anything. Having a downtime when students aren't joining continuously makes this possible.
Also, the workload for customer support is extremely high during enrollment periods. Most things are streamlined, but prospective students have questions, problems with emails/payments, and any number of other random things. I pride myself on being lightning fast with my support and this is only possible when enrollment is time-blocked.
Once enrollment closes, I can shift my focus to the enrolled students and continuing to improve the processes, etc. on the overall student experience.
The open/closed period also encourages cohort waves so more students are on the same page at the same time. You definitely _can_ do everything in your own time, but sometimes it's more fun to do it with people.