For paint I would do white, pearl and black opaque, and a shiny silver and/or gold.
for transparent I would want black, red, blue, yellow, a dark green, a brown, and fluorescent green and yellow.
I would think you could do most paint jobs with that (albeit with more custom mixing).
Past that I think you are getting convenience of having to mix less, or fun things like interference colors.
A lot depends on what you are fishing for, and the waters.
If I was fishing Lake Erie for walleye, I’d use purple more. If for smallmouth in the Great Lakes golds and browns due to the gobies. Lake of the Woods is tannic, and gold has always been popular. If I was in Texas I’d probably use lots of red-orange. If I was trolling for trout, maybe some fluorescent pink.
It’s addictive. I would also, if starting out, make sure to have a good clear to use between colors, heat set it and it’s a lot easier to wipe off the next color if you’re not happy with it.