No, he's saying you compress CBR, then encrypt. Not compress CBR -> gzip -> encrypt or something silly like that. CBR audio codec, then encrypt gives you a con

No, he's saying you compress CBR, then encrypt. Not compress CBR -> gzip -> encrypt or something silly like that. CBR audio codec, then encrypt gives you a constant-bitrate stream indistinguishable from randomness. That's pretty much the gold standard. (Of course, that still only encrypts content, not metadata. You can encrypt a phone call in such a way that a watcher gets mathematically zero information about what's being said, but the watcher still sees who is calling whom, when, and for how long. Hiding that is much harder.)