I remember being very fond of xhtml. It seemed much more logical and sensible, every beginning having an end, all things in balance. I don’t really know what the argument against it is/was?
It is a valid usecase of html to be used to splash a layer of paint on top of your business model in a situation where you’re too busy to think in a mode where the concept of ”system correctness” makes any sense. It’s not a system in this context at all, it’s my flyer in a trade show so don’t you dare come being all pedantic on me :)! (Sure, CMS manages the markup usually nowadays. In the nineties html was used as the actual user facing layer though.)
Of course, we can discuss whether that culture of busýness was ever actually constructive, but that’s a discussion for another day.