Anthropic's public writing style is very different from Claude's because it's written by humans. Even in their job ads they ask candidates to not use AI for any writing (or at least they used to).
Makes sense. Steve jobs didn't let his kid touch apple devices.
Yes. AIs are a lot better at coding than they are at writing. I author less than 1% of the code I push these days, but still write the grand majority of emails and posts. Probably I would do it 100% human if it was high stakes and I expected it to be read by millions.
The first rule of drug dealers: Don't use your own drug!
The phrase is, "don't get high on your own supply."