So what about the knife in the first post? I'm still struggling to figure out why it's there. It seems completely misplaced, useless, and actually detrimental to the otherwise nice design.
Let's change this up a bit.....
Your index finger is the only thing that really controls precision.
If you are using something like an axe or hammer, your index finger does very little, most of the work you do with tools like that involves force, and the control part is generally controlled by your arms.
Let's look at a pencil.
Great example...
First, try to draw a line or circle without using your index finger as part of the grip.
Next, try writing your name holding the pencil as far away from the tip as you can.
Then, try it even halfway down....
Point is, you have very little control because when it comes to finer work, your index finger needs to be close to the end of that tool.
Take an exacto/utility knife as an example. Very short blade (usually an inch or less) great control.
The purpose of a choil is to give you the ability to move your index (control finger) closer to the tip, while still allowing you to keep the standard grip (something the "pinch grip" does not allow)
The end result is the ability to have much more control over the tip and the front section of the edge for work that involves more precision.
Whether that is important to you is a personal thing, but if you have tried a knife with a well designed choil, let's say an SMF, you will easily understand the point.....