Why do these modules not include IPEX and trace/chip antenna connections simultaneously?
I took a look around the Nordic documentation.

You don't need a jumper on the Nordic board because the RF connector it uses has a switch.


  The connector is of SWF type (Murata part no. MM8130–2600) with an internal switch. By default, when there is no cable attached, the RF signal is routed to the onboard PCB trace antenna.