Should you go off road then the removable tow ball gives you back the rear ground clearence LR designed in.

Good point!

I keep the detachable ball, in the boot

Primarily to keep the ball clean (even if covered), so as not to contaminate any pads in the caravan hitch
Plus, the ‘walk in to’ factor

I'll grease it before/decontaminating after using my trailer
Mine is the gooseneck, l wasn’t too bothered about a fixed, or detachable, when l bought the Kodiaq, but only removables were available