I think you'd be surprised by the amount of website you can scrape without an headless browser.
Even Google SERP can be scraped with a simple HTTP client.
Even Google SERP can be scraped with a simple HTTP client.
I imagine, for example, building on the SERP example might hit a wall if you added logged in vs not logged SERPS, iterating over carousel data, reading advertisement data etc.
From what I can observe, 2/3 websites can be scraped without using a headless browser.