When this was mentioned at last night's LACBA Appellate Courts Section meeting, Justice Grimes emphasized that this actually really is important, and PJ Rothschild chimed in (delightfully sarcastically) to say that the formatting guidelines really don't matter at all--unless you want your brief to actually be read!
There were many fun zingers last night, including Judge Ikuta characterizing the short and often opaque Ninth Circuit memorandum dispositions as haiku-decisions.