In the end, Jacob found that most of the knowledge related to the runes in the shop was already present in the Witch Palace, and the only thing that wasn't was the knowledge of space runes.
So, he didn't waste his money and bought some runic blueprints that could really be helpful, as well as knowledge of magic smith and alchemy that wasn't in the witch palace.
Afterward, he bought materials for those blueprints, recipes, and magic weapon designs. Especially the magic guns. He knew it was time to move on to magic technology and combine it without his own.
Jacob's future ideas and the most powerful weapons in his mind were straight out of fantasies, and the technology needed to create them was not something even the unique plains might have. So, he naturally has to combine magic technology.
