MSIX-packaged apps use MSIX to give users an easy installation, uninstallation, and update experience.
Unpackaged apps don't use MSIX - instead, they use a non-MSIX installer.
Sparse-packaging offers a hybrid between these two approaches. Sparse-packaged apps use MSIX to package, but they use a non-MSIX installer (like unpackaged apps) and they run with package identity (like packaged apps).
Each type of app can be published to the Microsoft Store, but we encourage you to MSIX-package your app to ensure that end-users enjoy a seamless installation and update experience.