what is the point of "in private browsing/incognito mode"?

[Kenshin22]

besides porn
since I know that's what a lot of people use it for

[letalis]

Looking for a gift for the person you share the computer with & you don't want them to find out.

Or, most commonly (bar porn) just for Googling weird & embarrassing things, that might generate questions/mocking from the person that shares your computer.

[Unclued]

To help avoid targeted ads that give you options based on your browsing history. To not give companies free information that they use to make sales. To not let anyone know what you're doing because you just don't want anyone to know, no matter the reason. There's a lot of points to it and the vary from person to person. It's just an option in the end.