Split white light through a prism and you don't get a ranking from a bad end to a good end. You get a fan of every wavelength at once — red through violet, none higher or lower, just light spread out by colour.
Now split the light of a star. Threaded through its spectrum are fine dark and bright lines — and here's the wonder: every element leaves its own exact pattern of them, a fingerprint. Hydrogen signs one way, helium another, iron another still. Reading those lines is the only way we know what the stars are made of.
So a spectrum was never a scale of more-or-less. It is a signature of what something is made of.