you spelled egomaniacal wrong in this sentence, btw.
The whole point of the power score is to show what might be a meta sleeper as it has favorable match ups into the common decks… which is why it’s not just “winrate” like has been mentioned here.
It’s basically a measure of what is performing in this snapshot of the meta. That’s not to say it’s predictive, because the meta is always moving - especially at the highest ranks.
Edit: It shows what is working in that meta, shaman might be a sleeper based on low playrate, I mean. It shows what is strong based on what is played. It’s a weighted number.