My feelings exactly. I gave it a try yesterday on a lowly laptop running Ubuntu, just to see if I could practice some basic stuff from time to time when away from the gaming (and most definitely non-portable) PC. Gave up after 10 minutes or so, as it’s nearly impossible to control even the simplest aircraft (e.g. C152) with a gamepad.
I think the issue stems from the fact that Xbox Gaming Cloud has the hard requirement of a gamepad and hasn’t been designed to work with keyboard/mouse. I found some Chrome extension that emulates keyboard/mouse clicks and axes, and fools the service into thinking it’s a gamepad. But I doubt it’ll make any difference to MSFS Cloud if it can’t be configured to use keyboard mapping in the first place. I’m not sure even sure it can work with a HOTAS?
Obviously others who are already familiar with controlling MSFS using a gamepad will have no trouble with this. But trying to transition from a 100-button home cockpit to a gamepad is nearly impossible.
Nevertheless it’s still a magnificent feat that a software title as demanding as MSFS can run on the browser of a lowly laptop without hiccups or lag and people already paying for the Ultimate subscription will most definitely enjoy it. But I don’t think anyone should use it as the main reason to subscribe to that service.