Earlier quoted context omitted.
Mainly because it isn't semantic and breaks accessibility features. If you find yourself writing layouts like this you're probably ignoring a bunch of useful stuff like etc. Unless you manually configure it yourself, screen readers won't know what's important to read, tabindex won't know where to jump around, and form fields won't know what values to offer.
> isn't semantic It's certainly better than calling everything a div. > breaks accessibility features I don't know if I'd call it breakage to just... not use them where they should be used. Of course if a real tag exists that adequately matches the author's intent, that should be preferred over a made-up one.
It's not. For semantic purposes is the same as . So on the surface they are equivalent.
But if you are in the habit of using custom elements then you will likely continue to use them even when a more useful element is available so rather than so in practice it is probably worse even if theoretically identical.
Basically divs with classes provide no semantic information but create a good pattern for using semantic elements when they fit. Using custom elements provides no semantic information and makes using semantic elements look different and unusual.