Optimizes mental resource allocation

A system architecture is a representation of the system that exists or will one day exist in real life. For that system architecture to be good, it must demand the mental resources of a user of that architecture. This means that it must sufficiently compress excessive details while avoiding over-compressing information that requires attention or is of greater importance to the system.

In other words, a good system architecture will require the user of the architecture to devote more mental bandwidth and focus to the parts of the architecture that have higher stakes or are more fragile.

When a system architecture achieves the proper balance of friction and seamlessness in the right places, then the user of the architecture can trust that architecture to sufficiently direct them, and the user’s mental burden can be offloaded. The user trusts that they do not need to create extra friction for themselves when things need to be double checked, the architecture will provide the appropriate amount of friction for them.