The only real difference is being fairly certain that anything you buy on GOG will be DRM-free, since that is their stated policy and they offer the standalone installers for download. Granted they also offer a launcher like Steam, and if you’re only using that then you’re no better off; if a game gets delisted and you don’t have the installers archived you may be out of luck, depending on the details.
That said you are right, the problem is the laws and the publishers. But getting access to those offline installers certainly doesn’t hurt, in the meantime.
Supposedly, 666 being a bad number is a mistranslation, and the actual bad number is 616. This is according to an old episode of QI.
Or you could not believe in evil numbers.