I thought about one when I had my old KDX, but the stated max distance from sensor to speedo wasn't enough, as it's alot further on a motorcycle.
I ended up fitting a wired one, but I had to fit the wiring/mounting kit for a rear cadence sensor, again because of the distance from sensor to handlebar.
The specs might have changed over the years though.
I've previously installed the cheap Trailtech copies, with limited success. Had to extend the sensor cable which isn't a big deal, but I did find that it starts going a bit odd when going at any speed. Now the cable has been ripped out by undergrowth, I haven't been bothered to repair it.