The end of a course is not the end of learning! On the contrary, for long-term gains students need to revisit the materials frequently. They might also wish to review their work, the feedback they got, or even keep flexing their study habits with their Work Journal and flashcards. Therefore, once a course is over, accounts become inactive (the school stops paying for them), but students keep access to their history and study environment.
Of course, at any time, they can request their data to be deleted. And if they don’t use their account for 3 years, it’ll also be deleted in compliance with GRPD policies.