> The buyer is also signing up for a monthly payment. So clearly they have the cash to make an “extra monthly payment” or two up front.

I know of pilots who buy the +Cellular simply for GNSS and do not get a separate plan.

Charging more for the C-series hardware is understandable, but if there's enough of a 'transistor budget' it would be nice for the GNSS functionality to be more universal (since the N-series seems to be going into everything).