Not when you know what you're doing and don't use auto code generators.

What is "knowing what you're doing?" I'm honestly curious, because I handwrote most of the HTML on my website and I don't know how to have it cleaner than something like this:

  </div> <!-- footer -->
  </footer>
  </div> <!-- row -->
  </div> <!-- container -->
  

(If you actually look at the website, it will be pretty obvious that I'm no skilled web dev)

Indenting all of the tags would help, but that's probably about it.

    <div>
       <footer>
       </footer>
    </div>

In theory, maybe.

In practice, where the code is coming from 3 or 4 different levels of templating? Bets are off.

I use Twig for templating a lot, and I have to admit that while I indent per template, i don't even bother keeping track between parent and child.

But then, Twig has its own weird issues sometimes with adding whitespace so I've given up caring how templated html works altogether in that case.

Assuming a mythical "knows what they are doing" user, then parens aren't any different.

Are you really on hackernews bragging about HTML skills?

Bragging? I don't think s/he is bragging, but just saying that html can be done wrong.