Multiple pseudo cores required their user to know how and when to activate one or more of them at the same time whereas a single one once activated would follow its program until it was turned off.
It was the reason why Lith had decided to craft his first power core. To make sure that even someone with a bright red mana core like his parents could use several powerful types of magic with no effort and little training.
To assemble a power core, the Forgemaster had to merge several pseudo cores into one, making sure that their runes harmonized so that the resulting core would be greater than the sum of its parts.
Once Bonded with the metal, mana crystals generated a flow of world energy but during the Bonding process, before the mana circulatory system fully formed, the flow was actually a flood.