DRM can still ruin the user experience a lot.

For a simple example, I have bought Fallout 3 on Steam, but I cannot run that version on Steam on an old Windows 7 machine by default even though its specs are enough to run it, I need to do some workarounds to launch Steam in the first place, and at that point I'd rather download it from a pirate site.

How would my experience be on the same machine with GOG? I can download it directly from the site, or if I cannot connect to it because of browser incompatibility somehow, I can save a downloaded copy to my flash drive from another computer, then transfer its files and it works.

Some old games might not implement Steam DRM and therefore work with the file transfer, but it doesnt work all the time. On GOG it always works because no DRM.