I wouldn't even call it bad. In may ways it's good, actually. It's good because it allows signal to build a product that is relevant and usable. Phone numbers only connect people and are a bridge to allow all the perfect crypto to do the legwork. The knee jerk "phone bad" reaction is understandable, sure. But I don't think it's warranted for Signal. Signal would look like Keybase without phone numbers. Keybase (or their key exchange UX, at least) is great. But it's not the same product.