Trainers actually prescribe this stuff. It's because of a misunderstanding of functional training and the appropriate use of this type of unstable surface thing.
They THINK that it is challenging the core and improving proprioception while engaging all sorts of tiny muscles that don't usually get engaged. Sounds good on "paper" but it doesn't work that way. It's the opposite of what a healthy individual needs at the lower body to develop strength and power.
What this stuff IS good for is to fix chronic ankle instability. But you don't use something like this to fix problems that aint there or you'll end up with REAL problems.
This kind of thing can be good on upper body. Like db presses on a medicine ball. Not on the lower body. Basically think above the hips.
Let's just say whatever doesn't break your ankles leaves you with impaired power and agility and perhaps some bonus knee problems for you trouble.