Well, if your mac address changes every time you connect to a different network, Unity would be detecting and billing for a lot of false positives, so it would be a bad method to identify unique devices.
Except iOS will randomize its mac adress at each boot / after a while to prevent users being tracked by rogue WiFi networks, which is actually a thing being used to track consumers in commercial spaces etc. So that wouldn’t work.
Depends on your lifestyle and game choices. I have both (and a desktop PC). I would say 97% of my gaming is on the gaming laptop, and the remainder is split evenly.
Handheld is cool but often lacks good ergonomics for longer sessions, as well as limited GPU power. Desktop is obviously “the best” but for my games, my gaming laptop is good enough for 100+ fps so why bother going to my office and booting up the desktop?
The only time my laptop is not good enough is VR simracing, but that’s not a power problem, it’s just a matter of having all my simracing stuff hooked up to the desktop already.
Laptop beats handheld in screen size, power, compatibility, and controls for me.