There’s Really Nothing Private About Private Browsing 

As most of you already suspect, privacy today is mostly an illusion. Your favorite browser plays that illusion with so-called private browsing (In-Private browsing, Incognito mode, etc.) And we know that most people might think that using these private browsing modes somehow increases their privacy — but it’s just an illusion. About the only thing private browsing does for you is keep your browsing history from being recorded on your own computer. However, this too is an illusion because if someone wanted to track your browsing history for some reason and they had legal authority, they could get the goods on you from your ISP who tracks everything you do online.

So, private browsing is an oxymoron. It does not make anything private. The only reason I can think of to use it is if you we to keep some temp files and browsing history off your computer — and also to sign into multiple Gmail or Outlook.com or other online accounts which you have two or more of. Otherwise, there’s really nothing private about private browsing.