Ahh.. so it is just an ATSC tuner.
It doesn't have to scheduled recordings on those ATSC tuners
Nor integrate the guide data from those ATSC tuners and the sub channels.
Nor be able to handle if the reception of those channels bounce in and out.
Nor be able to properly work with the MPEG-2 encoding on those broadcasts, which are slightly different different the MPEG-2ish encoding on the sat based ones.
Plus have all the setup and testing screens for that feature to be in place.
And to make sure the units can handle signal overloads and multipath issues
But sure, after all it is just as simple as an ATSC Digital tuner.