I like to use steam deck when I travel. Denuvo can refuse to launch without internet connection to reactivate a license. Also if you exceed 5 activations in a day you can't play the game for 24 hours. This includes switching which proton version you use to launch the game, which is sometimes necessary if something like the audio doesn't work properly on the default.
https://www.reddit.com/r/SteamDeck/comments/wymoi9/psa_for_denuvo/
Yeah, it's something you shouldn't notice if you always have internet connection, but if you start playing where you won't always have internet connection that's when problems pop up. That's when you appreciate the DRM free games.