Main issue will be battery life.
Steam claims a 2-8 hour battery life, but has only a 4 hour battery life for a 10 year old game in Portal 2, unless you wanna cap it at 30FPS, in which case it goes up to 5-6 hours.
That makes it sound like if you wanna play Control, for example, which they're advertising prominently, the battery life would be.. 1-2 hours, if that, at 30FPS? '
Of course, it depends on your circumstances. Do you commute for 2 hours a day on a train? That might make it the perfect machine for you.
On the other hand, if you're looking to take it with you for longer trips, it's probably going to be of more marginal benefit.
The other things I'd be concerned about is how hot it might get, and how noisy it might be, but let's see how we go.