You need to dump your own bios off of your console but if you do own the console, the fact that you don't own the devices for dumping the BIOS don't make it suddenly stealing, despite being technically illegal. It's just a mutual loophole that both companies and emulating folk use to not fight with each-other, the people pretending to all having dumped their own BIOS since they own the consoles and the companies not minding since, well, most consoles that are emulated are at least last generation or before than, meaning they've sold enough and won't sell any more and the only thing companies would accomplish going after emulators would be to seem like assholes.
As for roms, that's another thing, even if you own the game, you're still not allowed to make copies of it on your computer, since it's copyrighted, though it is definitely moral to choose to play a game you own on your PC rather than on an old inconvenient console, so take that as you will.
For me in theory, the only real use of emulators would be regarding portable systems since a lot of good games are practically ruined by the tiny screens on which they are on. Playing them on a big PC screen does them justice.
As for roms, that's another thing, even if you own the game, you're still not allowed to make copies of it on your computer, since it's copyrighted, though it is definitely moral to choose to play a game you own on your PC rather than on an old inconvenient console, so take that as you will.
For me in theory, the only real use of emulators would be regarding portable systems since a lot of good games are practically ruined by the tiny screens on which they are on. Playing them on a big PC screen does them justice.
