There have been devices like that around for 10+ years now, and they all basically encourage illegal activity. The people selling them make their money on the cost of the device (typically ~$300). I've seen them demonstrated and the quality of streams varies wildly because most of it is illegally or questionably-legally streamed by non-official entities. The devices themselves have little to no support and aren't known for their quality. If you don't plan on using them illegally it makes almost no sense to buy one at $300 vs just buying a Roku, Firestick, or Apple TV for far less up-front cost.
Not to go on a tangent, I've just seen these things in action and they seemed janky as hell to me + the obvious dubious business model. It's basically the modern equivalent of old school "free cable" hacks.