Adding an plug is for a handheld radio to connect to an external antenna is, to me, an absolute piece of equipment. I have had two electrical failures in the last year. One was in VFR on top conditions that required using the handheld to communicate my plans to ATC. With no external antenna, transmissions and especially reception was poor. Then I had the plug and wiring to the external antenna done. The next electrical failure(voltage regulator death) ccaused no anxiety at all. Simply plug the handheld into the jack, plug the headset into the handheld and communicate beautifully and clearly.
My Cirrus will get this jack and wiring done very soon after I get it. Great piece of mind.