I agree with u/Inalial; they probably provide excellent protection at the expense of some flexibility and comfort.
I got lucky and found some Leatt knee/shin pads for like $15 so I decided to try them out despite the fact they were designed for Motocross or downhill mountain biking. They're surprisingly comfortable but you can tell that it was designed for a sport where you never fully straighten your leg. They'd be great for downhill but definitely not for casual use or pushing.
I only mention that because I'm assuming motorcycle gear is going to be similar.