Because the "treadle" pedal is the worst design I've ever seen in my life. I found that it required my leg to be lifted each time I wanted to go from forward to reverse and vise versa. Some guys say they put their toe under the front of the treadle and use it that way. It's just a stupid design. It also interferes with the only place you've got to rest your foot flat on the floorboard during operation.
The rest of the operator station looks like a tractor from a third world nation.
I much prefer the modern designs and dual hydro pedals side by side like you see on every other brand on the market. Safer, more comfortable, easier to use.