I'm not sure if you're serious or not. I think the connection that was being made is that, if you evaluate usage based purely on time, Pandora may have a ton of time in use. But, much (or at least some) of that time may be people who've left it to stream for hours after they've left.
Leaving your work computer on doing anything has nothing to do with the usage of a mobile app. He's not leaving his phone on playing music overnight at work.
Pandora isn't claiming to be the most used app in the world, they're claiming to be the most used mobile app in the world. People take their phones with them and for battery life alone are not likely to leave them playing music while they aren't listening to it.
I think Pandora stops if you leave the app playing for some hours without any interaction with the app. Most streaming services do that to save bandwidth.
The terms may prohibit, but in my observations, I know of many restaurants and small businesses that do it anyway. I'm sure most ignorant of the policy, but how many would stop anyway if still known of it.
Which makes you part of Pandora's claim that they're the most used mobile app. Leaving a desktop computer streaming music on at work has nothing to do with mobile app usage.
It illustrates that music apps are likely to be in use for very long periods/proportions of time. maccard's comment was quite relevant; it's not at all unreasonable to read in "and other people might use pandora similarly to the way I use spotify".
It's obvious that music apps get used for a long period of time. That's why Pandora is one of the (if not the most like they claim) most used mobile apps in the world. Leaving Spotify on at work while you aren't there is not the reason why.