[homarp]

because commercial platform dies, the content vanishes.

because commercial platform decides to block searchbot indexing and once again content vanishes.

[viraptor]

Or commercial platform decides it doesn't want to deal with alternative clients and just bans people using them.

[toastal]

Or US sanctions tell the entity they’re no longer allowed to serve the clients in a particular country cutting off a chunk of the user base.

Or a user merely wishes to remain anonymous & that shouldn’t be a problem for them (provided they are acting in good faith).