I'd prefer a "Data last updated at <timestamp>" indicator somewhere. Now I know it's live data and I know how old the data is. Is it as cute / friendly / fun? Probably not. But it's definitely more precise and less misleading.
No, a dark pattern is intentionally deceptive design meant to trick users into doing something (or prevent them from doing something else) they otherwise wouldn't. Examples: being misleading about confirmation/cancel buttons, hiding options to make them less pickable, being misleading about wording/options to make users buy something they otherwise wouldn't, being misleading about privacy, intentionally making opt in/out options confusing, etc.
None of it is the case here.
Of course, in the tech industry, you can safely assume that anyone can detect your scam would happily be complicit in your scam. They wouldn't be employed otherwise.
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edit: the funniest part about this little inconsequential subdebate is that this is exactly the same as making a computer program a chirpy ass-kissing sycophant. It isn't the algorithms that are kissing your ass, it's the people who are marketing them that want to make you feel a friendship and loyalty that is nonexistent.
"Who's the victim?"
You're able to hover a bar to see its exact value. Very precise there. No misleading info.