This means you can't pass the game around to your friends or sell it afterwards, which completely ruins the purpose of physical media imo. I mostly play PC these days so this doesn't affect me, but it's a disappointing direction for console games. At least they could've used an empty disc that has proof of ownership.
It does. But any decent USB C hub will work too. It's a PC! The main downside compared to the Switch, is that the transition between handheld and TV isn't as smooth, due to the different screen aspect ratio (Steam Deck is 16:10, most TVs are 16:9). From my own experience, I usually have to restart the game for it to fill the screen properly.