Physics modeling is arguably the most important task of computers. That was the original impetus for building them; artillery calculations in WW2.

All engineering modeling uses physics modeling, almost always linear algebra (which involves large summations). Nuclear medicine—physics, weather forecasting—physics, molecular dynamics and computational chemistry—physics.

Physics modeling is the backbone of modern technology, it's why so much research has been done on doing it efficiently and accurately.

We're using general relativity to calculate sattelite orbits - fuck your point of sale system iff our sattelites come crashing down we're gonna have much bigger problems lol.