It is useful when you have started a function and make another thing (another prog or when you go in another place to drink a beer)
when you come back in front your computer, the function is successful, and you know how many times that was ellapsed :)
That will be useful when you will want to make a same function in the futur!
You don't think any time to see your clock : so an internal Moi's clock begin/end function success will be a must :)
Not so difficult I presume :)