Invention is a product of inventorying

This is so far the most convincing reason for why it is important to commit a lot of (useful) things to memory.

Joshua Foer explains:

Where do new ideas come from if not some alchemical blending of old ideas? In order to invent, one first needed a proper inventory, a bank of existing ideas to drawn on. Not just an inventory but an indexed inventory: to find the right information at the right time.

This is what the art of memory was ultimately useful for.

From Joshua Foer’s Moonwalking with Einstein