I wouldn't do the same for an instrument approach because I can go down to DH as long as I have the vis by the FAF, If I see the runway at DH, I can land because I will have the required vis. Tower can say whatever they want as far as vis goes after the FAF and I can continue legally as long as I have the flight visibility during landing.
The winds on the other hand are changing constantly, especially on gusty days. I can't disregard tower winds and say "Yeah but the wind sock only showed 20." You get guys asking for wind checks and tower gives the winds when he clears you to land. I don't want an ATC recording of a 21 tailwind should something happen on the runway. When it gets close to the limit, it could just as easily be over the limit when I land. It is not a matter of whether the airplane is capable. I know it is, and it could easily handle more. It is a matter of covering your ass. If the FAA ever looks into your flight, do you want them to see that you exceeded the limit when you landed?
My question for those who don't see my logic... Would you land with a 20 knot tailwind with an FAA inspector in the jumpseat? It is legal yes, and it can also be safely done. But are you going to then calculate the tailwind compenent every time tower gives the winds to make sure it is not 21? Wouldn't it be easier to land on runway 4/22 and not worry about the tailwind component?
For those of you who would land with a 20 knot tailwind with an FAA inspector in the airplane... Why would you choose the runway that is 1 knot away from a possible certificate violation?