What does incognito mode actually hide?

Incognito or private mode does exactly one job: it stops the browser on that device from saving your history, cookies, and form entries once the window closes. It is privacy from the next person to pick up your laptop, nothing more.

Everyone upstream sees you normally. Your internet provider logs the sites you visit, your employer or school sees traffic on their network, websites you sign into know precisely who you are, and Google, once you log in, connects the session to your account. Google in fact settled a multibillion-dollar lawsuit over users misunderstanding exactly this.

Legitimate uses: shared computers, signing into a second account, checking how a page looks logged out, and shopping for gifts on a family laptop. For privacy from your network, you would want a VPN; for privacy from the sites themselves, largely, there is no button.