Why do you need a LogOut button?

Preface : struggling with unscrupulous users (various types of votes, ratings, ratings, etc.).

And suddenly the thought came: why bother to give an opportunity to go out and log in as another user ??

This feature is probably on any site where there is authorization, including on the habr, but why is it needed ???
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To start many different accounts?
Maybe it would be better to give the opportunity to edit your single account and close the possibility of relogin?

Once thought:

You can make the option “do not remember me” active by default. If you go, for example, from an Internet cafe - cookies are not created. If from a personal computer - uncheck the box and authorization from this computer is stored in cookies (you can make an option for how long).
In the case of a “home” computer - when the whole family goes to the same site - as a rule, they create individual users and the cookies will be stored in individual folders. It seems so.

Upd:
Understood, it will not work. Thank you for the discussion.