Security-by-obfuscation is ridiculed but I'm a firm believer that preventing yourself from getting owned when someone is able to type 3 letters `env` is a worthy layer of defense. Even if those same secrets are unencrypted somewhere else on the same system, at least make them spend a bunch of time crawling through files and such.
It's ridiculed because its no protection on its own when an attacker is motivated. Its fine to add as an additional layer though if you want to make your space mildly custom to protect against broader attacks.
I don't see how its necessarily relevant to this attack though. These guys were storing creds in clear and assuming actors within their network were "safe", weren't they?