Quite a lot of swords and daggers have eared pommels: Yataghan, Shashka, European, ancient Persian etc.
The PhD dissertaion by Nakov ( Rivkin, thanks a lot!) offers an explanation. It is so simple, that I wonder why nobody (to my limited knowledge) suggested it before.
According to him, these sword just recapitulate the primitive "bone dagger"
http://www.art-pacific.com/artifacts...s/bneknife.htm
It was likely very widespread in the primitive societies due to the ease of its manufacture, good stabbing efficiency and remarkable convenience of the gripping, with the thumb on top. Later, separate blades ( stone, bronze, iron) utilized bone as a handle ( again, very easy fit) and thus the tradition was born!
I have thought about it many times, but never voiced it
No doubt, many others had the same idea but ... never published it.
It is so simple and obvious that it must be correct!