Didn't realize what I was missing till I tried a nice set of hydraulic discs, I'll never go back.
I don't agree with the "gap is much smaller than people would expect". Have you tried a decent hydraulic brake? I raced on and off road, was a bike messenger, designed and built (from tubes) a mtb frame, and bike commuted nearly every workday of my life. Disc brakes have significant advantages over any rim brake.
Don't knock them till you try them, I was dubious myself.
I actually just sold my carbon wheels and downgraded back to aluminium until I buy a disc bike for the long term.
The worst problem is after a few minutes of constant breaking, which you have to do if you're descending a mountain carefully and care for your life, the rim brakes on carbon start to squeal and you lose a lot of braking power. You also used to risk delamination but that isn't that big of an issue on the newer wheels.