My GMG has WiFi, which I love. I work from home. The WiFi lets me easily do all-day cooks in my back garden, while working in my home office in the front. I can keep an eye on where the temperature is, without the distraction of going out there to check it.
Can I use the grill without WiFi? Of course I can, and I sometimes do, if I happen to be cooking while working in the garden.
Meanwhile, my old Traeger currently doesn't even have a control board. It is wired up to work flat out all the time it is switched on. As I generally use it for either flipping burgers or - with a stone - as a bread oven, this is not a problem.