Hype.
Take two different shaped cores, but with the exact same numbers, say 2.50 - 0.042, use the same cover stock, drill them identical and have ThrowBot do it's thing. All things being equal, they should roll identical. Numbers are numbers, science is science.
There is no magic core or cover stock. A core defines spin (early spin, late spin), the cover stock defines length, the bowlers axis rotation, axis tilt and speed define everything else. It's the magic combination of a particular core and cover that matches your physical game that makes a ball special.