I've seen similar shapes in wood from Amazonia and Hawaii, but, not in a knife. Weird. I'll look for pics of the wood versions.
While I won't argue that it's a main battle weapon, if you think of it as a fork as well as a double knife, I think you can see how it would be effective as a weapon. Forks can be useful for tripping, pinning, and parrying.
However, I can also believe that it was for status. That's a good default explanation too.
My 0.0000000002 cents,
F