This device replaces a "box" ADSL in a locality (home it is a seaside resort) where the cable rate is well below the mobile broadband (I reach 5MB / sec, with a package "Nomad "). It connects to the Ethernet box (it even has 4 ports) or WiFi, as usual. This router is also expected to serve as a backup to an ADSL connection in case of failure of the latter, with a fifth Ethernet port dedicated for this use.
One complaint, the price, which in my opinion should quickly move below 100 for the time you pay the novelty of these 4G cases.