This is the premise of HLE, or high-level emulation. You emulate the CPU (if it doesn't match the current one), and then implement all the APIs it hits. It's more like WINE than BSNES.
The one place where you may end up emulating something with precise timing is the audio processor; the Gamecube and Wii for instance used a custom DSP that had to be emulated fairly precisely, after the instruction set was revere-engineered.
The one place where you may end up emulating something with precise timing is the audio processor; the Gamecube and Wii for instance used a custom DSP that had to be emulated fairly precisely, after the instruction set was revere-engineered.