It can be very important or not an issue. If the GC writes some damaging things, it can be an issue at some school and even squelch admissions chances. A glowing one with the right key words from a known school to college who knows that school can be a huge plus A blase, form letter kind will likely not detract or help as student if that is the usual fare from that school or counselor (could even help some kids–it’s not like all info will help a student).
I agree with Pizzagirl.