It means neither of those, actually, just that CSS supports only multiline comments.
Multiline comments remain prevalent across ecosystems though (like in JS and Python). If you believe they’re bad there too, that’s fine, but the fact is that it would be an anti-pattern to go against those established standards.
The fact that CSS only supports multiline comments doesn’t mean multiline comments are good, it means CSS is badly designed.
It means neither of those, actually, just that CSS supports only multiline comments.
Multiline comments remain prevalent across ecosystems though (like in JS and Python). If you believe they’re bad there too, that’s fine, but the fact is that it would be an anti-pattern to go against those established standards.