It gets engine type, road name, and road number as well as info regarding engine specific features, i.e. icons for a tender doghouse light on a steamer so equipped.
If they haven't already I believe there has beenm talk that the modules will be phased out because the information can be entered manually.
I'm guessing running a loco via cab1L is going to be similar to running under TMCC with the exception of finer speed control, and still having access to the quillable whistle.
"You won't know what your missing", because the cab1L will lack the display/icons or controls telling you its there.
You went all out on a transformer, I'm suprised you stopped a bit short on the command system.
Having said that, my guess is you should still be happy with the operation of your trains regardless.