Well, I didn't know some games on gog had drm, but seemingly a vast majority of them on gog are. I hope they start labelling them. Either way, gog usually makes it a mission to point out you don't need a launcher to play gog games. A huge number of steam games will not launch without their steam integration or drm check working. Speaking practically you get a clear choice to keep your games when you buy them on gog. On steam not so much.