Another advantage of hydraulics: less brake lever force. You can brake powerfully with 1 finger using hydraulics. This is not a challenge to cable brake owners. If you can brake powerfully with 1 finger too, good for you Fact is, the hydraulic system is a force multiplier and you can brake harder with less effort.

Why brake with 1 finger? I learned this as a child on dirtbikes: hanging on to the bars with all but 1 finger is a really good idea in rough terrain, at speed. My suggestion if you're going to practice this is use your middle finger so your index finger and thumb can make a circle. That's your surest grip. (Note that you don't have to squeeze the grips hard-- I advocate a secure grip, not tight.)

Jump to the opposite extreme: if you brake with all 4 fingers, you're hanging on only with your thumb. It's very easy to hit a bump, root, whatever and lose your grip. Crash is nearly guaranteed after that...