But why do I need to write CUDA kernels? The CUDA kernels I need already exist, and I don't particularly care if writing them was so horrible that it required s

But why do I need to write CUDA kernels? The CUDA kernels I need already exist, and I don't particularly care if writing them was so horrible that it required scratching your eyes out and sacrificing kittens to demons - I would care about the (re)writing effort only if I was considering other hardware that doesn't yet have the support that CUDA has as then I'd actually have to do that myself.