An RGB value points to a single color, but if R is "really into trains" and B is "repetitive behavior" and G is "susceptibility to sensory overload", then it's basically the same metaphor as a multi channel audio mixer, except understandable to a different (and likely bigger) pool of people.
It doesn't have to be exact, but it's counter productive when it is clearly and meaningfully incorrect though. That's the problem with the two dimensional [0,1] scale as well.
That's just the limits of it being a metaphor. Audio mixers also only have a finite number of channels, but are also much less familiar to most people.
