As many have already said, there is no definate value to put on it. I left my previous job partially because my wife and I were tired of the constant travel. On the other hand, I did accumulate a decent amount of points and free trips so we took full advantage of that. A business trip to an interesting destination once in a while is a nice break from the office. Repeated trips gets to be a drag.

I would put zero value on it or perhaps see it as a negative, because no employer would pay you less, dangling the status and points in front of you. There are probably more people that would rather not have to travel than have to.