Years ago, I was on the observation deck of Toronto's CN Tower, where they have a glass bottom section that you can walk on. I was not thrilled by it, and especially not thrilled with the kids who were jumping on it.
I know it's safe, maybe even safer the flying (which doesn't bother me in the least). But looking that far down through glass.... no.
Now add water! And now, you have a glass-bottom swimming pool that dangles off a roof in Houston. Tell you what, I'll let someone else swim in that.