... generally controlling "stuff" with an app, and they are the first to have invented that, then that's their novel idea and it should be patentable.

Like the invention claims are specific enough that it only covers wood pellet grills, the controller has to be authenticated with the cloud (Probably to prevent other people from hacking your grill), and the user input has to be directly tied to a rate at which the pellets are fed into the hopper. That seems like a pretty reasonably scoped patent. Like the scope of that is clearly disputable, but if GMG can't show that they had that invention in hand and in practice on or before Oct. 23, 2015 (The priority date of the patent), then Traeger gets that monopoly, and that's a good thing.

If someone wants to compete with Traeger, then invent a better device. Or a better way to control the heat. Or find someway to do it via bluetooth without a need for cloud authentication. There are plenty work arounds. But Traeger (IMO) is justified to go after someone who is selling grills that read on their patent. Or be a patent troll and invent an improvement on Traeger's existing product, then approach Traeger about incorporating the feature within their own devices in exchange for a licensing fee.