I cant seem to find convincing evidence that a multidimensional php array is more useful than a database seems much more useful and easier to implement than a MF'ing DATABASE
Here's my take on it... If I'm not mistaken, you'd have to load the array into memory with each script call. A DB will retain data indefinitely. So, you wouldn't use an array to store persistent data. Even if you didn't need to store changed data beyond 1 script call, if your array is pretty large it can take up a lot of memory, and CPU cycles to load the array every time the script is called. This can cause delays, as well as an angry hosting provider if the problem is too bloated. So, why bother with an array? Well, if the data set isn't terribly large, and your need to access and/or manipulate the data doesn't need to be external to the script (like another instance of the script, or a different script), then go with the array.