There can be good reasons to keep an installer (or APK file) after an installation is complete.

It's down to the software writer of whichever program it is to decide as to whether the installer should be auto removed after installation or not, and as far as I can recollect I believe I've only ever seen one installer subjected to a 'self delete' routine after installation, and that is Adobe Flash Player. Pretty much the same reason as when you download an installer onto a computer and it's still there in your download folder after the program has been installed.

So I was wondering what would happen if I would just leave 'APK files' ticked on the main screen and it would not delete the currently installed versions. At the moment I go through the list and tick each apk one by one if it can be deleted or not, which can take quite a bit. However, seeing this list I am not sure if I could just use this function (and it would delete only those where a newer version is installed) or if this would uninstall all apk files in this list (which would be not good). Of course I just would like to delete the files with the status 'newer version installed' and not the currently used apk files. As I was unsure if this would include apk files of apps that I currently use, I clicked on it and there was a list of apk files stating a status 'newer version installed' and others 'installed'. I have used the cleaner yesterday and I analyzed the phone, it found some apk files to clean. I was wondering which APK files CCleaner deletes?

Ccleaner android apk