I have one. I am super happy with it. I can load my Kart on and off the trailer and never have to lift it. When I practice in Stockton, I am usually the only one there, so I would be stuck without it. Also, I am a Master and older, so I don’t want to waste energy lifting.
It’s surprising how small the motor is, but I guess if you gear down enough, it works.
It’s uses a lot of parts and different aluminum stock everywhere. Even if you simplify the design, it might still be a lot of work.