In the past, the Dolphin emulator was banned because it had too much of an advantage over the real hardware due to reduced lag and faster loading times. Even outside of loading screens, the faster loading times made gameplay more consistent because the game is constantly streaming information from the disc. Fast loading times and low lag made the sprint cancelling technique much easier to pull off since the timing wouldn't be affected by those things, which gave emulators a distinct advantage over the real hardware.

These days, Dolphin is a much more accurate emulator and it makes a good effort to emulate lag and loading times as accurately as possible. Personally, I doubt it's perfect, but it's close enough that emulator runners don't have the advantage they would have had in the past.

With that being said, there are some things to keep in mind about Dolphin. First, any settings that give players a gameplay advantage over the real hardware should not be allowed. For example, the CPU Clock override should be disabled, and any settings that make loading times faster should be disabled. In the near future, I'll have a list of all the Dolphin settings you should be using and I'll put that in the rules page. In general, the default settings are your go-to, but you can turn up the resolution and enable anti-aliasing and whatnot if you want. Dual Core is also fine, as it only makes the emulator easier to run on your computer, as far as I know.