People wish to feel safe. One path to safety is controlling or managing the environment. Lack of sufficient control produces anxiety. But control is only possible if the environment is predictable, i.e., relatively certain knowledge that if I do X then the environment responds with Y. Humans use models for prediction. Loosely speaking, if the universe is truly mechanistic/deterministic, then the goal of modeling is to get the correct model (though notions of "goals" are problematic in determinism without real counterfactuals). However, if we can't know whether the universe is truly deterministic, then modeling is a pragmatic exercise in control (or management).

My comments are not about simulating the universe on a real machine. They're about the validity and value of math/computational modeling in a universe where determinism is scientifically indeterminable.