I find it very interesting that, while carved in wood, the hilt nonetheless mimics the structure of a bone handle. An analogy comes to mind, with early Greek temples. Stone architectural details (metopes, triglyphs, etc...) were derived from the earlier structural wooden joinery. The material changed, but appearance was maintained out of convention, even when no longer functional or natural.
I imagine the choice of handle material was also subject to availability. Much easier to use a material that's readily at hand, than go out and hunt or stockpile material for future use
.
Thoughts...
On another note, nice blade
I've been puzzled by the abundance of crowits. Some of the new/touristy examples that have been shown on this forum and that pop up on ebay sometimes have lots of them.