Then, why not create a platform for predicting the performance of any cryptocurrency or a platform for predicting future trends in the market or both?
This concept of gambling would be prone to heavy manipulation.
It already has. Some months ago, before the official approval for EFTs of Bitcoin to be approved by the SEC in the United States, someone working for Cointelegraph released a false news on the alledged approval being positive and imminent, which obviously made the markets to increase (price of Bitcoin included). It was revealed later that person had also set a big gamble on the casino Rollbit (using their leveraged future markets), to capitalize money off their own Cointelegraph article.
For some reason I cannot find articles about it on Google, though, but I recall the whole situation ended up being the start of much outrage from the gambling community and those who usually trust Cointelegraph to get accurate news on the assets they invest in.
We are not even talking about a whale, though, just someone working for the crypto press.