How Cloudflare blocked a monumental 7.3 Tbps DDoS attack

What does this botnet do when it's not performing a 7.3 Tbps DDoS? Yea it's probably regular folks computers, but what "wakes up" the botnet to attack? What makes an attack target worthwhile? Presumably something this large would be on someone's radar...

The Command-and-Control part of the botnet would be whatever component they build to instruct it to attack; often using some dummy website they register and have the compromised clients poll for changes with instructions.

I think an increasing amount of them are state actors or groups offering the botnet as a service.