This, too, is entirely personal preference. I've tried it and found it resulted in too many colors for my brain to assign individual meanings to, and then I couldn't even benefit from syntax highlighting anymore because those colors also blended into the rainbow of text.
The differentiation benefit is not. Personal preference is what tool you choose to deal with spoofing, eg, you could also use a different font for different symbol ranges instead of colors.
> I've tried it and found it resulted in too many colors for my brain to assign individual meanings to
Well, you don't assign individual meaning to individual colors, but to color ranges which a given type can vary over. For example, going from green to yellow could be the range for variable names, so you associate that range with variables
Which color ranges have you tried?