I have the original Ally and a Windows laptop for one reason: I can't play Destiny on Linux. That's my main game. I don't want to get my account suspended for playing on Linux. So, I deal with Windows, even though it sucks.
I got the Ally to play Destiny 2, and it works perfectly. I play almost daily at lunch time in my car. I love it so much. Can't do that on a Steamdeck. Granted, the Steamdeck is a marvel, but I really needed a Windows machine.
FYI, that fine line is called a vinculum https://en.m.wikipedia.org/wiki/Vinculum_(symbol)