Yes, the adapter can do everything the other OBD2 adapters can with Forscan, but it also does J2534. Yes, it is not economical for most people, but I do have a need for the adapter after installing the keypad. You can use it to do keys as well, for example. I got the keypad free with Fordpass...
Not true. You can absolutely install the keypad without the dealer. It requires two things - the right OBD2 adapter and the right software. I don't know if Forscan is capable of it (provided you have the right adapter), but I haven't found a way with it. You need an adapter like this...