This element is particularly useful for two problems that may occur while merging merge modules:
The first likely problem is that in order to properly merge you need to have certain tables present prior to merging. Using this element is one way to ensure those tables are present prior to the merging.
The other common problem is that a merge module has incorrect validation information about some tables. By ensuring these tables prior to merging, you can avoid this problem because the correct validation information will go into the installer database before the merge module has a chance to set it incorrectly.