“Competitive” queue is for balanced matches. “Casual” is for the quickest match possible.
If people are avoiding the competitive queue because they think they aren’t skilled enough, they’ve got it all wrong. In the competitive queue you will be matched with people close to your own skill level, WHATEVER THAT SKILL LEVEL HAPPENS TO BE.
The competitive queue will take a little longer to match you up, but for me at least, it has been well worth the wait so far.
Please give it a try, even if you don’t think you are a “pro”.