It doesn't matter what the names are, the point is you can have a plugin that changes one color to another based on their names and what you can see. The names are a much smaller search space than "all possible hex codes".
I'd argue that the 147 named CSS colors are still too many (but definitely better than the ~16.8 million sRGB colors). Regardless, since hex codes are used in practice, they would still need to be dealt with.