What difference does that make?
I think what you might be eluding to is that if you went to the financial cost of buying it as an extra, you might well need to convince everyone that you spent your money well ?
Just guessing....
In answer to your first question......I do use it sometimes, but all I have stated is that my gear change is extremely quick/slick and smooth so I can change gear easily fast enough without using the quick shifter.