Huh? Only if it gets decompressed few times I would say, because it's so extremely slow at it

Like a software installation that you do one time. I'd not even want it for updates if I need to update large data files. The only purpose I'd see is the first-time install where users are okay waiting a while, and small code patches that are distributed to a lot of people

(Or indeed if size is important, but then again bzip2 only shines if it's text-like. I don't really find this niche knowledge for a few % optimization worth teaching tbh. Better teach general principles so people can find a fitting solution if they ever find themselves under specific constraints like OP)