The chief difference between the two is about security and authenticity. A signed app is guaranteed to be authentic and the integrity of the app is assured. The user can feel safe that the app has not been tampered. Any attempt to tamper will render it unsigned and is flagged as such. A signed app or driver is associated with a digital certificate that identifies the publisher of the driver.
In Windows 11 you can run unsigned app downloaded from anywhere(not from Microsoft Store). It could work, but your security is lowered. Sometimes its full functionality may not be available. Windows will notify if some driver is unsigned. You may get a message such as this one and the Smart app control on your laptop blocks it.
================================
"Smart app control has blocked part of this app"
If you see this message, it means that an app, service, or piece of hardware that you’re using has tried to load a driver, app, or other file that isn’t properly signed.
================================
