What's the rationale for b"..." in this example?

[Chris Angelico]

On Wed, May 16, 2018 at 9:02 AM, Skip Montanaro
<skip.montanaro at gmail.com> wrote:
>> Personally, I never use the str(..., encoding="...") notation; I prefer
> to use the
>> .decode() method of the bytes object.
>
> Thanks. And thanks for the other responses. I obviously didn't have my
> thinking cap on this morning. (It was too late in the morning to plead lack
> of coffee.)

You plead lack of coffee until you plead caffeine overdose. That's the
way of things. :)

ChrisA