From someone who actually does this stuff:
The claim is very accurate. Maybe not for the biggest websites, but very accurate for a self-hosted blog. You are not that important to waste compute power to set up a whole ass headless browser to scrape your page. Why am I even arguing with ChatGPT?
Yup another trick is to only serve br compressed resources and serve nothing to clients that don't support brotli. A lot of http clients don't support brotli out of the box.
I take it further and only stream content to clients that have a cookie, support js and br. Otherwise all you get is a minimal static pre br compressed shim. Seems to work well enough.