In many cases the more simulation-focused games are used by people who really like racing cars, or flying planes, or driving tractors, or whatever, but can't do it as much or in the expensive equipment they'd physically prefer.

There is a lot of variance in games as to the fidelity of what they're representing. Most shooters won't teach you anything about real firearms or bows and arrows and most racing games have little to do with real cars, but there are flight sims that have physics and controls directly modeled on real equipment.

There have been real piano training games. I'd imagine any instrument could be with modern audio sampling and analysis if people wanted to pay for it.