Short riders

I wouldn't say they make you better but it could make you more comfortable so you would ride more aggressive. the shorter seat could be just so he can touch the ground on starts if he's like RC. foot pegs i'm not really sure of though, i know a lot of guys change the peg height just a bit.

Yeah it’s just a comfort thing. I’m 5’8”, I’ve shaved seats and cut subframes for years to lower the ass end a bit just to get more comfortable. Lowering link can do the same thing but messes with it the rate the suspension works at, and can jack up the handling pretty well

I have really short legs and can't reach the ground but I like keeping my seat and pegs stock. I found that cutting the seat just increases the standing distance and makes you lazy and want to stay sitting and you also feel the base of the seat hammering you when sitting through acceleration bumps. The only time it's a hindrance having the stock seat is on concrete starts so I just use blocks.

They make you more comfortable which makes you ride better.

Everyone is right, it's mostly a comfort thing.. but no one asked what kind of riding you're doing! If you're riding on an MX track then you'll rarely be touching the ground other than at the start. (Unless you wipeout or need to plant your foot for some reason or another). If you're riding Enduro, touching the ground is crucial. It's why guys like Johnny Walker have such a big edge over other pros like Graham Jarvis. If you're just messin around in a field then it doesn't really matter, and if you're on flat track then you'll basically be dragging your foot around every turn (but you'll be so close to the ground that even a 5ft rider could touch)..

at the end of the day, it depends what you're doing. I would say why ride out of your comfort zone? .. if you can shave your seat and get away with dropping your rear suspension a bit.. why not? .. it will make you an all-around better rider on all racing platforms.