It's not needed on smaller screens. The switch does similar things. It's a common tactic on handhelds to disable those sort of features as they add no noticeable improvement.
The switch does it for *some* games when running portably and then enables most things when docked. A lot of that is battery management.
The steamdeck does not really have a concept of dual modes, per your own statements about playing on a bigger screen.
And I completely disagree that AA isn’t needed on smaller screens. You can see aliasing at any screen size.
Again, perhaps it meets your threshold of quality. That does not mean it meets mine nor does it mean that the form factor somehow obviates it. It just means that we have subjectively different preferences.
But again, I disagree that “it’s not needed”. That’s not why games will disable AA in handheld mode. AA is expensive and a cost they try and mitigate with art direction that tries to avoid much of the losses.
The steamdeck is not just playing games designed for a small screen. Many games suffer from shimmering and shifting. Whether that’s an issue for you or not is independent of whether they exist and might be issues for others.
