LESS is a CSS pre-processor that elegantly extends the language features of the world's most popular styling syntax, but using it today requires extra processing. Modern browsers should add native LESS support to make future developers more productive.
I disagree as well. There is no standard for LESS; Vendor support will be a nightmare.
I love using CSS pre-processors, but that's what they are: pre-processors. They're supposed to make my life easier. As it stands, LESS can be updated at will, with little concern towards backwards compatibility. If LESS gets a breaking update, guess what, none of my code breaks unless I update my LESS compiler. The CSS is untouched. If LESS was added to the browser, we wouldn't have any of that flexibility.