That makes sense, but what else are people supposed to do, the natural thing is to click the first time available, so hundreds of people would be trying for the same time. And between that and Slinky, it's basically as bad as the virtual queue where if things weren't perfect in 2 seconds, you get nothing.
Heck, it'd be better to pay to be in a virtual queue than pay for a return time that won't exist when you try to checkout.
I think the whole thing is an embarrassing shambles, just saying what I think the rationale is.