The United States spends money on war as a superficial means of helping the underdog. There might be deeper, underlying motivations, but we have always been champion of the underdog. Other countries spend money on war as a means of obtaining more power and control.
There are a couple of premises in the question that might have to be debated. The first would be the definition of "superpowers." The modern definition of the term is probably going to be different from the definition of the term as early as two decades ago. In defining, "superpower" in the modern sense, I think that a more encompassing definition of "war" might be needed. For example, during the Cold War, the concept of war was a strict militaristic one, where different spots on the globe represented the battle for superpower ideology. Yet, the modern condition of a "superpower" is more economic, in my opinion, than anything else. Nations like Brazil, India, and China can be seen as more of a "superpower' willing to use economy and commerce as a "battleground" than anything else. I think that this might be where the idea of "spending money" in order to make it could be evident. In this, the superseding element is capitalism and its proliferation is defining modern successes for the current superpowers and nations striving to be it. I am not in doubt of the idea that many nations wage war and seek to spend money on it, but I think that for me, the question seems to be embracing a paradigm that might not be in as much existence today as it was in the past.
You can take what I say with a grain of salt because I am an American, but I do not believe that the US (the only superpower in existence at the moment) engages in war for "glory" and I do not believe that we "love" to engage in war. I do believe that we make mistakes and sometimes enter wars that we should not get involved in, but I do not think we do it for glory or for the love of war.
Because the US is the only superpower in the world, it tends to feel like it should get involved in everything. So many parts of the world are related to American interests, so the US feels the need to get involved. This can be seen quite clearly in the Persian Gulf War of 1991 and the later invasion of Iraq. In these cases, the US felt that it was necessary to maintain or ensure stability in the Persian Gulf region because that area is so important to the world's economy. We may have gone about it the wrong way (particularly in 2003), but I would argue that our goal was to maintain stability in the world, not to seek glory or because we love war.
Again, I agree that we get involved in wars we should stay out of, but I think we do so because we feel that we should try to make sure the world runs smoothly. We are the only superpower and feel that it is our responsibility.