You can make the same statement if someone did VQ all day only to not be able to get onto the ride at all. The only good thing about VQ is the fact that you'd get to go on other attractions while "waiting". If anything goes wrong, it might lessen the blow to someone if they hadn't waited all day in line, but it might mean something to someone else. Especially if the attraction, let's say for example, was running smoothly all morning, or even into the afternoon and just as it was your turn it's down for the rest of the afternoon, or evening. I'm sure a lot of people would kick themselves if they had a chance on it if they just waited in the first place. Also, regular queues get a "ruby pass" if they close the ride, where as I doubt someone who waited in the VQ wouldn't get the same privileges. They'd have to either way, or VQ the next day.
It's just my opinion that you cannot have a VQ if the ride is as unpredictable as Hagrid's. On top of that, it will essentially make another queue and get even longer if there is a delay, so what's the point? I do not know how great VQ is for VB, but when I stayed at CB only a couple of months ago, I consistently saw lines outside of my hotel room of people waiting in line for this "virtual queue" for water slides. Granted wasn't that long of a wait, but the whole point is the fact that you're allegedly not waiting and in that case, they still were. When the parks first opened the lines were even longer and ridiculous due to the popularity and newness of the park. So, honestly, if you really think about, it wouldn't more than likely wouldn't work regardless. Disney clearly has a different method than Universal does.
VB's virtual queue is not comparable to what Hagrid's virtual queue would be. At VB, once you are in a virtual queue you can't enter another queue. You need to hang out in the wave pool/lazy river or find a ride that has no line at that time.