not really true, its personal choice if you use a mount or not, it only gives you 10 speed, so on high lvls it might be considered useless as it wont change that much, the only thing is the animations look a bit frame limited maybe thats why you have a feeling like that, but yeah, mechanically, mount is just +10 speed, when you're a high lvl it doesnt change that much some people just prefer to stay in their outfits (I do even tho im low lvl, as Ive played before mounts were in the game and i just stay so)