I have used different Vermeer chippers in the past and I can see those cables hanging down as being a pain when feeding in slash from a pine tree. The whole idea is to not have to trim branches. Though when feeding branches, I have a hand on the reverse handle while lifting - feeding with the other hand.
I have a Mackissic SC-183 tow behind, I am the only one allowed to feed the top, I am pretty sure that could lift a small person off the ground and suck them in up to at least the arm. You never actually feed the branch in, you push and let go or just chuck it in.
I refuse to use any of the bigger chippers without a WORKING reverse feed, especially the chuck and duck type run by a Ford I-6 with no safety features (drum), those things should only be feed by a skid steer, imho.