It's a genuine scientific question: adding a useless feature slows down NN training, but how much? Is the impact as negligible as can be expected? There's no r

It's a genuine scientific question: adding a useless feature slows down NN training, but how much? Is the impact as negligible as can be expected? There's no reason to spend lots of brain cycles on low-value theory and possibly wrong estimates instead of lots of GPU cycles on a conclusive experiment.