So I have put that blade in use for first time and the result was more than satisfying.
The knife is used holding like this and cuts the leather like cutting butter. also the wide straight cutting edge allows to cut very straight or smooth curve as I wanted to.
Here is a shot of cut edge. almost shining very clean cut. The best thing about this edge is very crisp 90 degree edged corner..
As I have hearing about this type of leather knife, "once you have used it, can't let it go..." well, I think that is truth.