On Friday, March 7, 2014 8:15:11 PM UTC-6, Guido van Rossum wrote:

. . . but my guess is that he's actually trying to argue on behalf of Python users who would benefit from using Decimal but don't want to be bothered with a lot of rules. Telling such people "use the Decimal class" is much easier than telling them "use the Decimal class, and always put quotes around your numbers" (plus the latter advice is still very approximate, so the real version would be even longer and more confusing).

Yes, that is correct.   Although, I would modify "with certain rules".  I mean, its ok to expect some 
rules (I think that's what we mean by semantic).  But rules that seem to go against the grain of 
the normal human experience ...  like quoting a numerical input. I mean if you tell me as a programmer
that's what I have to do, well that's what I have to do. On the other hand (the hand I'm really concerned 
about) if you tell a naive user they have to quote their numerical inputs-- that seems like the wrong 
approach.  Yes, its much better to say, "Please use the Decimal module".