Need? Sure, I suppose you don't need them. I've run games with only humans in them, too. But that doesn't mean the non-humans are pointless.
If you are playing the non-humans well, they give you something other humans can't - non-human psychology and perspective, and the occasional game mechanic. There's nothing like a villain who lives for centuries, so that they can wait for decades to come to fruition. Or one for whome there's a good mechanic for eating your brain on a combat timescale
If you are playing the non-humans well, they give you something other humans can't - non-human psychology and perspective, and the occasional game mechanic. There's nothing like a villain who lives for centuries, so that they can wait for decades to come to fruition. Or one for whome there's a good mechanic for eating your brain on a combat timescale