Many emacs macros are prefixed with 'with' keyword in elisp. In an imperative language like python, with statement is used to create a temporary variable like this,

with controlled_execution() as tempVar:
     some code

However, in macros like with-current-buffer, with-temp-buffer, with-temp-message, i see with is not used for similar purpose. Can someone explain, in elisp macro, when to prefix a macro name with prefix 'with'? And because these macros are expected to clear their temp variables, do they have any side effect on the main program?