Whilst they look pretty - very striking actually - they suffer from the slight draw back that they fail in every engineering principle you can apply to a wheel.
The rollerbearing and seal speeds are almost as high as the road speed.
The brg & seals are "in the muck".
The wheel is no longer a entire "structure" - relying on the bearings to prevent distortion.
rotating interia is much higher - bearing / seals / drive being almost at tyre diameter.
very small amount of damage results in a jammed wheel.
And other reasons I can't think of at the moment.