While that is true, I don't see it making any different in Primid's case. Literally just about anyone who has played Project M has experienced Brawl and the Subspace Emissary. It is very obvious that Primid's attacks were based off of items and fighters in Smash, so it is hardly a surprise to think he could translate well into a fighter. So the only real excuse people could have is being too lazy to look into it when it is suggested, or writing Primid off because it is a lesser minion comparable to a Goomba (Which, in my opinion, is still a lazy excuse).
Primid clearly has the easiest cookie cutter layout for his moveset you could possibly ask for. He is essentially a Brawl's very own version of the Mii fighters mashed up into a single character. Or for a better example, Primid basically represents Smash itself. I'm not at all implying Smash needs self-representation, nor should Primid be the candidate to do it if so, but it is clear that Sakurai's intentions with Primid were to make "The enemy who encompasses Smash Bros.". His various forms represent streamlined items in the series, and his attacks are inspired by the common moves seen in various veterans in the series. It just makes sense that Primid would be the prime example of a good Clone Engine character. If that is not a good enough reason to look into this character, then whatever to you naysayers. Your loss.