As much as GOG/CD Projekt have more than their fair share of problems, usually their versions of games work, can be preserved, don’t require as much bloat, launchers included, and usually don’t require 3rd party validation. And like others said, besides Wine and related, and installing through Steam as external games, you can also install stuff very easily through Heroic and the sort. So I’d say it’s the better option indeed.
Agreed with Magician and RmDebArc, and besides that, it could also be for the challenge, for the enjoyment, or because the vision of the dev only works in such a platform. And with emulators that allow commercial use around, the developer can also publish his games to modern platforms without having to rebuild the whole game.