As of right now, I find my Google Wave account to be utterly useless... and this is not Google's fault. At this point in time, Wave is obviously in the early-adoption Beta stages. Not many people have the service and it is a service that is integrated tightly around communication and collaboration with people.
Since I only have a mere 4 contacts on Google Wave and we do not really have anything to use the tool for yet, it seems like a waste of time. Also, I have not really found many add-ons/extensions that are beneficial to me and there is not much of a selection to choose from (yet).
As I said before, with time Google Wave will have room to grow and expand. When more people begin using Wave I am sure it will begin to find its place and make more sense as a practical tool.