Could someone have a million addresses with 1 coin at each address and they wouldn't make it on the list?
Can one person have multiple addresses?
Yes. Everyone has multiple addresses associated with a wallet, but each address is only controlled by one person.
Are the top addresses the popular exchanges wallets?
Some might be. If you know some addresses and they are not listed, please feel free to send me a message
Why are these stats useful?
Information about major holders and insider transaction data is useful for trading stocks. The same could be said for cryptocurrencies.