Autofill actually increases queue time in lower elo
In lower elo, queue time is already relatively short (most of the time), autofill really doesn't shorten the already short queue time by much. instead, what happens is these players get autofilled to support, they dodge, and the nest lobby someone else got autofilled and dodged, so technically increasing queue time by increasing the chance of peeople dodging.
It is actually ridiculous how 3-5 minute queue time can lead to 30-40 minutes of waiting for a game due to people dodging. Honestly I rather have the old system with 1 minute queue time and everyone negotiate their role.