This is not simple at all.
What happens if you don't have the money available? If you want to provide some guarantee, how would you do it without locking up N x $100 forever? What are even numbered hours - which timezone? What happens if your transaction doesn't get accepted within that timeslot? Etc. etc.
Okay, I'm simplifying a little bit. It wouldn't work exactly like that. You'd lock up $100 (or approve the contract to spend up to $100), specify the time I'm unix timestamps, and leave it up to the recipient to claim their money.
That's sort of besides the point though. I'm just saying that you have the ability to implement whatever ad hoc or arbitrarily complex payment logic you want without relying on a middleman.