Issue with these things is that they eventually get shut down. You're better off setting up a Kodi box (basically a Raspberry PI) or something, at least that way the hardware is fairly standard and can be reused for something else if the service goes down.
I doubt this box is legal, but they can milk it until the authorities decide to shut it down. Really what would be nice to see is if they could come up with a streaming standard and you could subscribe to streams legally. Like companies would setup their own stream server/services but the streams would use a standard that works with boxes like this. You would just enter a URL/ID or something in the box, and boom you have that channel. Essentially it would be like a cable box but fully over the internet and not dependent on one provider. Of course some streams could be free as well like publicly funded broadcasts etc.
As for how these streams work my guess is that people who are paying for cable can use some kind of software to decode it and then stream it. Some kind of HDMI capture or something like that.
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