The main downside is battery life, which is why most people use desktop or server (IE plugged in) machines as their main seeding devices. But you can also just set libretorrent for android to only seed when plugged in.

Its also perfectly fine for mobile clients to be mostly leechers rather than seeders. All that’s important is that there are at least some seeders for a torrent. If there’s even two seeders, then we’re already doing better than youtube for availability.