I've always viewed them as the same snake, different lines. If I had butters, I'd breed them to more yellowy snakes to improve that buttery goodness. If I had lessers, I'd breed them to bright, creamy silvery snakes to improve the qualities of those. But in general it seems they both grow up looking nearly identical no matter what they looked like as babies, lol!
And both of them are GAWGEOUS!
And then of course a ball python is a ball python is a ball python, be it a desert, pastel, pied, normal, or any other 'morph'. All the same snake, they all eat, poop, and hide. We choose the colors and patterns we like best, why get so worked up over morphs vs. lines and all the drama it causes?