Cutting the cable, lets talk options and media setups

Kodi is a open source software available on a number of platforms that allows streaming via "add-ons" from various sources around the web (tons of discussion here).

There are a number of add-ons that are not supported by Kodi that will stream copyrighted material. In fact they have been specifically disclaimed by Kodi, and they have gone after people that have conflated Kodi with those add-ons.

There are number of companies that are installing Kodi to dedicated hardware (usually on Android) and reselling those boxes, which is legal, though subject to Kodi's open-source licensing terms. The one you linked appears to be one of the more shady outfits.