Adam DeJans Jr. wrote: “Modeling the world isn’t the same as making decisions in it! A common trap is to spend months building a perfect simulator… a beautiful digital twin with clean architecture, smooth animations, and every physical nuance modeled. And yet… when it comes time to actually make decisions?

No policy. No framework. Just dashboards and “what-if” buttons.

Always separate the two:

Modeling the system (the physics, flows, stochastic processes) gives you a sandbox to play in.
Designing the policy (decision model) means deciding how you’ll act over time, based on what you observe in the system.” Link