I don't need a reason...

I think that it would be possible to grind a bit of a notch on the bottom to allow the cotter a little more clearance -it would make this tool look a little more like the bikesmith version. I'm sure the jaw length is big enough for most any crank, it's just teasing the bits onto the crank and over the bits of the cotter that stick out. It's probably necessary to unscrew the pusher part entirely to get it over some cranks/cotters and then screw it back in. Kind of a PITA since the pusher will want to fall out of the end of the bolts as nothing is holding it in. I wouldn't say that this version is quite as nice as the BikeSmith one but I bet it works just as well once you get it teased onto the work.