At first, students got to use what they were already use to, but when the pandemic got painful and everybody flooded to online, thing went crazy. Discord is freaking enormous in that area rn. Servers for High school classes, university cohorts (ie. CS'24), university programs (ie. Electrical Engineering), There is even a course I am taking at uni where we have an official server with the teaching team, profs, auth with uni credentials, and a freaking ad-hoc ticketing system.
It is bonkers how much systematization is done through these bots.