I do use it for the mastering process. All of my bounced files are brought into Waveburner where I will then arrange them as to how I want them on a CD (it does matter what order they are on a track... to me, it tells a story). I will then see if I need to apply any plug-ins, such as EQ or compression. Remember that your tracks will have been mixed on different days, so you may have been in a certain mood when you mixed a particular song that may sound radically different that the last song you mixed. Thus, when you hear them both together, you may wind up going WHOA! because there may be no relationship between the tracks, but you like the order. Thus, you may need to adjust one of the tracks, or both, to make them "bond". Sometimes, you need to do this in the opposite direction as well and shock the listener.
Regardless of what you are doing, it is often the final step before the CD. That is how I view Waveburner.
jord