If you are asking for yourself and no one uses your phone, then Reddy's answer has the idea. But if you're asking because you saw this on a partner's activity, which is legal if they give you permission to use the phone, then I've been there, and here is possibility number 2. It is when the individual reads their account to the device. Why would they do that? I'll explain.
If you are trying to communicate with people or sites and you don't want someone to know but have to make it look like you aren't hiding anything and you don't want to leave anything behind by accident. Then you can't pause your activity in Google, that may give it away. You don't want to go through your activity feed and miss something you need to remove. So you remove your account after backing it up, and I add an account you do the activity with. Different email, social accounts, contacts. Everything. Then when you're done, you sync the second account and remove it. Add the first account back and restore the backup to the original form. Or a hybrid of said process. Now I think every time you add an account to your phone, said account would get a "device connected update app usage" log in Google activity feed.
Or if you use a browser like DuckDuckGo, you could anonymously log in to Play Store and use the app in the browser. Then when you uninstall an app with the Play Store or app section of settings, your device message would show.