The key benefit in my honest opinion is personalization. There are dozens of switches to choose from, they all feel VERY different from the rest. Learning the feel of each switch is gratifying, and i'm a much faster typer on my MX Clears or MX Blues than I've ever been than using the scissor switch on macbook keyboards (and I've been using macbook keyboards full-time pretty much since highschool) my WPM also jumped about 20-30 after a week or two... That's not saying much as a coder since you aren't paid by your WPM... my wrists don't hurt nearly as much, my fingertips also don't feel like they are slapping dead weight anymore. The actuation of a mechanical IS NOT at the bottom of the keystroke. Some switches are in the middle, and others are near the top of the key press. Getting used to the key travel and when the key actuates is important. To me, it's so friggen hard to compare. It's a love it, or hate it thing. But I strongly feel that people that invest the time and effort to get comfortable with a switch they like, it pays off.

Edit: I know some people that have used MX Blues their whole life that switch to MX Reds or even something completely out of left field like a Topre switch or a Gateron, and they instantly fall in love with it. It's a matter of finding the switch that works for you and makes your fingers little happy clams :)