const conveys additional information.  It says &quot;this name will not be rebound,&quot; not just to the reader, but to the machine interpreting this as well.<p>As a reader, I know that after reading a const line I don&#x27;t have to check if someone rebinds this name before each use site -- it&#x27;s impossible.<p>Interpreters and static analysis tools use this information to stop you when you write a piece of code that rebinds the name, asking &quot;did you really mean to do that?  You said you wouldn&#x27;t.&quot;