I suspected this since Sworn to the Sword, but it’s nice to see confirmation from these last two episodes:

Pearl had to train to be able to summon her weapon because Pearls aren’t supposed to fight. I always thought it was weird that she liked swords so much and even knew how to use them, yet fought with a spear. Then I realized it was because she couldn’t always summon her spear: in the flashback from Sworn to the Sword, she’s seen fighting with said sword. It was probably her primary weapon before she became able to summon her spear.

Meanwhile Amethyst - a quartz, a gem made for fighting - is able to summon her weapon without even trying. She even goes “listen Steven, all that practice stuff is no fun!” It comes so naturally to her because it’s supposed to, it’s what she was made for. Obviously a soldier gem’s gonna have an easier time with a weapon than a servant one.

Really, it’s crazy to think that this was back in the first episode, all the way back in 2013. They had it all figured out since then.

And since I’m already talking about this, Garnet’s explanation is “you can link your mind with the energy of all existing matter, channeling the collective power of the universe through your gem!” I have no idea what this is supposed to mean or say about her. Maybe because she’s a fusion she doesn’t have hard wired directives like singular gems do? Can’t say.