MSI Apps may show as installed, but be unable to be removed because Patch My PC uses the MSI code to perform the uninstall. Scriptrunner can be used for the uninstall to ensure apps that show as detected can actually be uninstalled.
Patch My PC was used to install MSI App 7-Zip 19.00, 7-Zip 19.00 gets automatically upgraded to 20.00 outside of Patch My PC, but the 19.00 app remains deployed. In Software Center, 7-Zip 19.00 will still show installed, but clicking the uninstall button will fail to remove 7-Zip 20.00 because it's MSI code will have changed. While this occurrence may be rare, offering an uninstall button to the end user and having it result in an error is... less than optimal. Scriptrunner can search out the proper uninstall string and use that to uninstall the application instead.