Autofill being used prior to queue time hitting estimated wait time?!?

With the new autofill system I'm not sure what the point of even selecting roles is for instead of just hitting fill. I've queued for rank my estimated time for wait was 2:26 the first time I queued was within 1 minute and it autofills me into jungle when I selected top and bot as roles.

What is the point of even selecting a role if autofill is just going to place you into a random role you didn't select before you've even hit your estimated wait time?