It doesnt matter if he hides it or not, scam: n. A fraudulent business scheme; a swindle. Its the definition of a scam, doesnt matter what, are you going to write a new dictionary?
You don't need to write a new dictionary. They also fall under the definition of gambling whether you like it or not:
1.
play games of chance for money; bet.
2.
take risky action in the hope of a desired result.
This is also how I feel about casinos v HYIPs on bct. We are unable to vouch for any legitimacy for an online bitcoin based casino because there is no guarantee that its not just going to alt + F4 away with deposits after a while, which is exactly the same with a HYIP. Considering gambling vs scams IRL is entirely different because that 40 story casino isn't suddenly going to grow legs and try and walk away with your deposit.
Or I hope not. Although that would make a good Godzilla sequel plot.