> Another part of the PEP's reasoning was that this notation
> is difficult to understand at least partially because it 
> is rarely encountered, so "people don't understand it" as 
> a reason to exclude it from the documentation becomes a
> bit of a self-fulfilling prophecy

We know that isn't true because people already see it frequently in the tooltips for C functions.  What I've observed is that after repeated exposures, users learn to treat it as noise and tune it out.  I've not found a single instance where a user found it to be helpful.