It’s not just about the money as I said in the tweet! It’s about being (a little bit) paid for doing something I like (writing)
probably web scraping, along with SEO, is one of the most shameless niches in tech and is crammed with people with nearly zero tech skills and are only for the money. Maybe for your case you just happened to love web scraping, but this niche itself is the lowest of low. Thankfully Cloudflare and the low barrier to entry/increase of supply make sure that no one can make much more than he should (which is $0 imho).
Creating a technical book about a specific subject is a great way to advertise yourself as a freelancer/consultant as well.