Depends on a few things – weight, riding style, where you ride and preference.
If you’re heavy, ride aggressively and regularly ride lumpy 10 minute plus descents you might begin to notice the rear end becoming less controlled and possibly a bit noisy. My RP23 used to start ‘quacking’.
In practice given your description, probably not required for you. I’m 90 kilos and only notice my RP23 starting to struggle halfway down fast lumpy stuff like Stickspass and Llanberis descent. It also showed itself in Spain where the descents were as long as the lakes but ambient temperatures were higher. On slower more techy stuff that I generally prefer, the shocks generally working less hard and it doesn’t show itself.
I’ve got a piggyback DPX2 now and it was a conscious decision, but I was replacing my full susser and the question was ‘why wouldn’t you have a piggy back?’
IMO there’s nowhere outside of the Lakes, Snowdonia and Scotland that’s big enough to make it a real issue in the UK. Maybe a couple of Peak descents in a very hot summer.