DRM is part of an anti-cheat solution. Just like not being F2P is

If authentication is not properly checked, spinning up new accounts to evade bans becomes trivial. This is why so many live games will be “buy to own” or have different tiers in matchmaking that boil down to “spend five bucks on anything to play the real game”. And same with DRM checking for pirated copies.

The other aspect is regional restriction. Not sure if denuvo specifically does this, but you can pretty easily check what region a game was purchased for and what region it is playing in. If all those dirt cheap Brazilian copies are being played in Kansas? Report an error. It prevents people from exploiting regional pricing while still allowing those who have ridiculously low purchasing power to buy anything… and it mostly just screws over people who travel.