It also doesn’t prevent advertisements carried through the website’s own domain. For example, lots of video platforms send their advertisements through the same domain as the content’s domain, so if you block that domain, you’ll also block the possibility of watching any content there. That’s why you need to have ad-blocking within the browser.
This reminds me of a currently trending Brazilian meme (amostradinho) that I’ll translate here: “Huh, what audacity! In my presence? I like this way, the lil’ exhibitionistic, let me fill your ticket, ‘Once upon a day…’, and that day is today, it’s now!”