I don't know either, but I have a feeling that when something has already been downloaded but not loaded into the program, we can take the payware content local files and restore them. The scenario for something like this would be when we do a restore from a backup or load up another database.
I've had issues where the restored content didn't have an asset.tdx and the complete database had to be rebuilt instead of just connecting to it. In this scenario, the payware was marked uninstalled even though it was installed on my hard disk. The only way to make the payware active again in this case is to do a fresh download.
My hunch is the data will be marked active if this button is clicked, by going out to My Trainz and verifying that you do have permission to use the assets.
