So... why do you give your phone to other people?

Seems like a stupid thing to do if you have shit on it you don't want others to find.

when someone is married and he doesn't want his wife to check his phone. So he need to have passwords on both of Messages and Photos apps. so that's he's safe

That's only true if said person keeps things on his phone that he knows shouldn't be there...

It means you are guilty of doing something wrong and you know it.