The basic analogy that Henrik tries to draw is that if you want to find out how much energy you are using you have to go to your meter and check it. But how do you know when you are using the most energy? How do you know if you are using more or less than last month? The only way to know is to collect/store the energy amount somewhere so you can later go back and do some analysis. This is basically one of the main features of DB2 PE is to collect monitoring information (snapshot, event monitor) and store it, so you can go back later to do analysis on how much CPU or Memory have you been using, from who and when. It also just provides a nice way to visualize database monitoring information.