Because hydraulic discs have more power, and that power is so
easily dished out, you don't get tired on a long mountain descent.
You spend less time braking and more time enjoying the ride. You
also don't need to plan so far ahead into a corner, I had fewer
moments when I arrived into the corner with too much speed because
I hadn't anticipated my arrival speed correctly.
Control was the key takeaway impression. Having disc brakes
wasn't all about increasing speed on the descents, though that's
clearly an argument in favour of superior brakes, just having more
control at my own comfortable descending speed. But because I had
more confidence in my brakes, I was able to allow the bike to run
faster between turns simply because I knew I'd be able to safely
bring the speed down before the next corner.
With rim brakes, it is possible to find yourself in a situation
of being afraid to really let the bike run off at full speed,
especially if riding carbon rims and your skills and commitment
aren't pro level. Everyone has their comfort zone on the descents,
disc brakes simply increase that comfort zone and let you, and I
really believe this, enjoy the descents a lot more.
Sounds like disc brakes are good then, but I know not everyone
will believe me or feel the same way. I'm only writing this after
extensive time on various disc brake bikes, including the stunning
Trek Emonda. There's no greater test than actually putting this new
equipment through its paces.
Emonda Disc in action at the 2018 Dauphiné.