[kapowaz]

> If I modify one of my building blocks, I know that every instance of it will now look like this.

But that's based on your own system, which may be non-obvious to other developers. The rules of valid HTML dictate the situation in which you will encounter a given ID, so this communicates something to every developer who sees IDs used in a given selector. To me that's tremendously valuable, and far more useful than trying to graft additional meanings onto parts of a single classname.

Whether that system is BEM, OOCSS, SMACSS or some other syntax, this kind of naming convention isn't a native part of CSS.

[ahoge]

> But that's based on your own system, which may be non-obvious to other developers.

Yes, conventions are like that. You have to read the docs.

> [...] this kind of naming convention isn't a native part of CSS.

That's true for naming conventions in general.

Well, this stuff was added for a reason. If you know the rules, the SCSS and markup becomes way easier to navigate. Additionally, there are now many properties which can be automatically verified.

It adds structure which wouldn't be there otherwise.