What is /Users/username/Applications folder?

123bebop wrote:

So can I swap the apps from this user Applications folder to the main Applications folder without consequences?

Maybe.

There are two things you have to worry about.

1) Duplicates.

You should probable be running the latest version of all apps. Before overwriting an app in /Applications, make sure you are overwriting it with the latest version. That is, unless you want the older version.

2) Messy installs. It isn't just the Applications folder that is duplicated. There is also a user-specific version of the Library/Application Support and Library/Preferences folders. If any of these apps have data stored in those locations, then you will likely have problems. Nothing in these folders is documented. Nor is there any guarantee that you will be able to identify the files that are/might be associated with a given app. This can be a real mess.

PS. I'm on MacOS Ventura and I'm the only one using my computer.

Then the easy answer is to just leave it alone. It won't hurt anything.

I think that the Applications folder is where Apple's OS and apps are installed. The Apple OS is write protected and cannot be modified which provides protection against virus infections. The user's Applications folder that you are referring to is likely where your installed apps are placed and it can be added to or have apps deleted or updated. I hope this helps. I wouldn't worry about.

123bebop wrote:

It's strange that I can't find any information in Apple website. A clear (and official) explanation should be nice.

I don't know why these apps want to be there but, whatever, I don't care anymore.

Primarily it is a legacy part of the old NeXT system that Apple inherited for MacOS X 20+ years ago.

Years ago, installers would give you the option of installing software for "everyone" or "just for me". Most likely, you choose the obvious answer and migrated all those apps over the years. Or you had some old app that is still using an old-style installer.

Going forward, Apple is pushing all developers towards an iOS-style design where you won't see this kind of ancient seemed-like-a-good-idea-at-the-time thing. It's better to just get rid of such things instead of documenting them.

Those are apps that are installed for a single user. Also see: https://www.macworld.com/article/331913/make-macos-apps-available-to-a-single-user-instead-of-all-users.html