> How does a Linux port make it easier to port emulators or console games?
It helps emulator development by giving you something to work with inside of your emulator that actually has some tooling to let you look around and test out the system from the inside, unlike trying to get a game working. If Linux-N64 can boot, you can expect that a lot of your code is working properly.
Linux has debuggers and such and people (like me) are way more familiar with its stack than whatever they had back in the day. Software development would be way easier with all of that a support infrastructure.
It helps emulator development by giving you something to work with inside of your emulator that actually has some tooling to let you look around and test out the system from the inside, unlike trying to get a game working. If Linux-N64 can boot, you can expect that a lot of your code is working properly.