Here's a comparison using `brotli --best` on my app.
53K _long.css
38K _short.css
11K _long.css.br
8.9K _short.css.br
Both, dev and prod, have hashes because that's part of what CSS Modules uses to avoid collisions.Besides download size, smaller names improve parsing speed too.
Personally I don't think this reduction in size is big enough compared to making all css names unreadable and thus very difficult to debug.
It also makes it much more difficult to create personal browser extensions as all css names are now unreadable.