Watching some videos, and spectating in real life, I do notice a weakness in many riders’ galloping ability. It was something you were more likely to learn in the long format days: how to put your hands down, cruise up out of the saddle, out of the horse’s way, and then pick him up approaching a fence.
I think it would do riders a lot of good to gallop some racehorses if they intend to ride at prelim or above. You learn to be comfortable at speed; you learn to balance at speed; and you learn ways to slow or influence a horse WITHOUT using your hands (leave them on the neck!). You must be fit with a strong leg. It exposes physical weakness and overriding. Think of it as “flat lessons” for XC. It gives you more tools that you won’t learn in an arena.