from what i've heard it's fine for most fish and is a great way to have a super clean tank.
it may be stressful to fish that have a need to dig, but as long as you don't have any fish who may become stressed out if they can't dig then you should be fine.
My Oscar DOES see his reflection in the tank bottom. He sees it in dark areas of the sides, too. He's used to it now but it sure had him shaken up for a while there. Open mouth, turning green, etc.
I think that having a cleaner tank outweighs the stress of not digging, etc.