The MTH wifi allows you to use a wifi enabled device to talk directly to the MTH wifi unit, and if I read the manual correctly, you can interface a WIU to multiple TIU/AIU units, the WIU is basically the network connection for those devices, so you don't have to buy multiple WIUs. You also can use your home WiFi network with a WIU, where it attaches to your network and you talk to it via the home network (like using a wireless printer on your home network from your wifi connected device). The advantage of this for those who have wireless internet is that you can access the internet on your phone while using the MTH App, if you use the MTH direct the phone is talking only to the WIU. I suspect going directly to the WIU is going to work better because it will be right there where you are for most of us. In the case of someone with a mega layout, you likely would be better using your home network and have a wifi booster or boosters in the basement to make sure you have a clean signal, if the MTH WIFI unit is located a distance away, or has interference, your home network might be the better option.
As far as the expense, you don't need an expensive device to run this, you can buy Android based tablets for pretty cheap that would do fine. As far as downloading the app, if you don't have internet at home, you can always go to someplace that has free wifi like the public library, and download the app *shrug*. Put it this way, once your DCS remote breaks, you have to shell out $$$ even when they are available, and still will likely pay a lot once they stop making them and they aren't available from MTH. In theory there could be a cottage industry to repair DCS remotes if parts are available (in theory, a scroll wheel could be hacked with a replacement one used in some other electronic gizmo), but I do suspect that DCS remotes like TMCC base units will be available out there for a while.
