But you can have both! Why are we even arguing about this? Nothing is preventing you from having both strong cryptography AND obscurity, except for your insist

But you can have both! Why are we even arguing about this? Nothing is preventing you from having both strong cryptography AND obscurity, except for your insistence that hiding the key is a reasonable thing to do. It isn't reasonable. You should never attempt to hide a key using steganography when you can memorize a passphrase instead. Hiding the key needlessly breaks the "strong cryptography" part. But you don't even need to hide the key. You can still have all the obscurity you want by hiding the ciphertext and memorizing the key. If you do it this way, you'll still have your obscurity, but you'll also get strong cryptographic guarantees for free.