The bichwa hilt does appear to be deliberately designed to let you keep holding the weapon while using your hand for something else. I've seen the suggestion that this would be useful for wrestling. If nothing else, I think the hilt might be good for weapon retention during wrestling.
They might be good archer's daggers, along the lines of African loop daggers:
http://www.vikingsword.com/vb/showthread.php?t=1882