Does revolution ability queueing have a downside?

I have recently started doing more pvm now that I am close to maxing. I use revolution with manual intervention and I prefer to use ability queueing as it prevents me from spam clicking thresholds and ultimates, but I have heard people say things like "ability queueing will get you killed" or "it lowers dps."

Is this really the case? Can someone provide example scenarios to elaborate?

I don't want to practice bad habits so if it is worth turning off I would rather do it sooner than later, however I feel like it is easier to fire off abilities with it turned on.