Yeah, it's pretty expensive. Welcome to Vegas!
I just came here for a bagel and chai when I was staying at The Mirage for a quick breakfast before I started another day walking around the strip. The chai was really good, the bagel wasn't amazing but tasted fine enough. I think for the price you pay, they should spread the cream cheese for you, but whatever.
This is a good option if you want a quick breakfast. The line for the Dennys across the street was INSANE-skip that. Grab a bagel and coffe and you're good to go.