Associates cannot generally make investment decisions, and do not generally factor heavily into the decision to invest. A GP does; thus, impressing the GP on the 1st meeting makes it a real meeting. Impressing an associate on the 1st meeting is effectively useless, except for getting you to the real '1st meeting.'
That's how most founders see it, and why the advice of most former founders is 'avoid associates unless there is absolutely no way you can get in front of a GP directly.'
That's not meant to sound offensive, but it's definitely how most founders I've spoken to see it.