Not really a direct comparison. Yes they can store it on a hard drive, but where are they going to acquire the actual bytes? A cheap optical drive and a secondh

Not really a direct comparison. Yes they can store it on a hard drive, but where are they going to acquire the actual bytes? A cheap optical drive and a secondhand disc is a pretty good strategy and carries zero risk of legal issues because it leaves no trace outside your own PC, as opposed to say, BitTorrent. It’s just possibly much less convenient if the disc is hard to come by. Also (IANAL) but if you acquire the disc, back it up and then keep or destroy the original, it’s even fully legally sound.