I've gone to lots of talks on quantum error correction, and most of them start out with explaining the repetition code. Not because it's widely used, but because it is very easy to explain to someone who knows nothing about classical coding theory. And because the surface code is essentially the product of two repetition codes, so if you want to understand surface code quantum error correction you don't need to understand any classical codes besides the repetition code.

All that is to say that someone who had been to a few talks on quantum error correction but didn't directly work on that problem might reasonably believe that the repetition code is an important classical code.