Then when the MSIs aren't built correctly, they will leave you with a detection method that gets hosed when the software auto-updates. So you run your package manager, and it'll detect that your software is no longer installed, because the MSI product code changed for the newer version.
I mean we have so many ways to do software on Windows. Let's count them:
* MSI * EXE * MSU * AppX * Windows Features * dism * Windows Update * SCCM Deployments
Even just open up the "Uninstall Apps" control panel, or the old "Add / Remove Programs" and look how long it takes to load the list. It's pulling from like 20 different places in the registry and various places in the WMI database just to build that list. So when you want to use that as a detection method, good luck...