The point is that Starscream was thinking like a Furman character. If the McGuffin is not, (as Prowl more or less put it), a big shooty laser thingy, it is useless.
But, as shown here, Shrapnel's reaction to seeing the Matrix gives it power. Starscream knows the legends. But, he does not buy into them unless there is a direct benefit to him. He is too small-minded to see that *others* believing the Legends (and acting accordingly) is almost as good in practical terms as the actual legends being true.
When Starscream says the Matrix is without value, he is wrong. Yes, the main, narrating, character is comletely off base. Wowzers. Narrative complexity.
'Perceived value' being the key word there. Again, the point of the Matrix is to be chosen by it, to have access to its abilities. With out that, it is useless to anyone else. The Decepticons know the important role it plays in choosing the Autobot's leaders but again, that's useless with Optimus alive or if it hasn't actually chosen that 'bot.
The perceptioon of power is nearly as useful as actual power. If somebody seems confident, and competent, they enjoy the benefits of those traits almost as much as if they actually had them. (I have seen projected comfidence trump competence actually. It is really quite infuriating.) This is where rituals like "Chicken" or any sort of posturing (among people or lower animals) comes from.
This is why old animals sometimes get more aggressive, they want to ward off interlopers. My old cat was about 14 or 15 when she drove off a rottweiller. She projected enough aggression that the dog wanted nothing to do with her. (Granted, the dog was not aggressive, but my cat profited from seeing weakness on the dog's part.) My cat's willingness to fight was as important as her (then much diminished) ability to. One of my current cats was once intimidated and bullied by a cat that was ~18. (This would be like a healthy 22-25 year old being bullied by a 90 year old man.) It was the perception of strength more than the physical ability that mattered here.
Countries do the same thing. Us nuking Japan was as much for the Soviets as for the Japanese. And, the Soviets brutalizing the Nazis in Berlin impacted US policy. Neither of us really wanted to fight the other. The Soviets saw a material advantage for the US, (despite the fact we were in fact pretty well tapped at that point), and we saw a moral advantage for the Soviets (despite how fractious they USSR really was).
When I deal with clients, I generally do not let on about office politics here. Many of my clients simply assume I have far more influence than I in fact do. I am not saying "I am a very influential man". I sometimes gently admonish my clients, ("do you know what you are actually saying!?!?!? Seriously, I am very low on the totem poll here...."), to make sure they understand there is only so much I can do for them. Just the informatino they *assume* I have is amazing. Much of my power and credibility with them comes from perception. (Often after I correct them, my credibility goes up, because of confirmed honesty.)
The Matrix is valuable because enough guys will see it and say "wow". Starscream was too myopic to see that until he heard a guy say "wow, the Matrix". (Apparently, Starscream has a very limited frame of reference.) If nothing else, Starscream knows, or at least *should know, that the Matrix will motivate the Autobots to jump the way he tells them to.
Given the material advantage the Decepticons have, if Starscream cannot figure out a way to lure Prime and co into some kind of trap, he deserves whatever he gets. (And, hey, maybe Starscream is that small minded and stupid.) The Matrix has value beyond being a cosmic McGiffin if one is smart enough to exploit how others will react to it.
Dom
-enjoys stories that assume a real life frame of reference, even if they use giant robots.
