Yeah exactly: it's a fact that humans have been doing steganorgraphy by, for example, XOR'ing encrypted messages that are undistinguishable from noise with pictures where the lowest bits of pixels were... Undistinguishable from noise.

The recipient of the cat picture has the key allowing him to decrypt what looks like noise.

We didn't really think 100% of those cat pictures on the Internet were really just cat pictures did we?

Now of course this doesn't survive lossy re-encoding of the picture, nor rotation, etc. It's not like, say, a watermark.

XOR'ing a properly encrypted secret with bits that are by definition random (say from a picture coming out of a camera) is quite solid.

It's noise (except it not but it's impossible to tell it's not) and more noise. And they're XOR'ed and that gives still noise (except it's not but it's impossible to tell it's not).

And that's just one way to do it. Anywhere there's something that could be noise, it's a venue to do stego. Metadata with GPS coords? Thanks, you just gave me a few bits to do stego. The possibilities are really endless.

It's one of the reason why it's very hard to detect all types of data exfil and the "klepto" type of attacks (which is basically stego but hidden for example inside the "random" cryptographic parameters picked to sign messages).

Noise is just noise and indistinguishable from noise. Until it's not noise. But even then it's still indistinguishable from noise.