That's an interesting idea, definitely. I can think of a few spots where I would rather have a vertical bow than a crossbow due to potential limb contact issues. One drawback that I can see (for me) is that it would be awkward to shoot from a sitting position. The majority of my shots are sitting with my left elbow rested on my left knee, or even from an actual rest in a blind. It appears that the intention is for it to be shot from a standing position, which is no trouble if that's what you're used to.
Let us know how it works out. Might be something I could add to my wish list for certain spots and certain conditions.