“It would be great if people had to buy more of the thing,” says guy who makes money selling the thing.
You download them and back them up. What happens if the disc is scratched or your buddy drops a blunt on it?
The DRM is the key part of that. So the answer is DRM-free, not physical media. Especially since all games get patched these days.
If it’s still being published or if a second hand copy doesn’t cost more than your buddy’s annual wage.