>>714794438nta but if i buy a game off gog or if i pirate it, it's mine forever and can easily be backed up, redownloaded, etc. even on steam you can do these things as long as your account exists, you can also apply cracks to the steam version or just outright emulate steam's calls via injectable dlls.
if you buy a game off a disc, assuming it isn't just an activation code for steam anyway and doesn't still require some form of online activation, the disc itself is easily lost, stolen, destroyed, etc., and is specifically designed not to be able to be backed up. if anything happens to the disc, it's gone forever.