I feel like it would be an interesting learning tool cuz I learn a ton on here and it gets me writing without anyone having to hold a gun to my head. I mean like even essay-length or at least essay-worthy treatments of things I respond to in longer-form, and even for the shorter-form stuff
I don’t see why you couldn’t use a defederated version of Lemmy as a kind of private forum. That said, it’s most likely easier to use a good old phpBB forum, there is still tons of companies offering you to host one, it’s a bit outdated and not that popular anymore, but various clubs still use one because it’s what we set 15 years ago, and it’s still working (and to be fair, I like that forum keep information over time while it’s a hell to search old thread in whatsapp/discord). A lemmy might be a more modern form of a forum for a club/school/whatever. I don’t know whether you have “private” forum like you would with the good old phpBB like forum
Searching discord is a nightmare
I also wish I could search communities here to help make things a bit easier to find