Potential for fraudulent activity makes something a scam? That list is gonna be long

"Gaming"[0] companies are audited for the expected value each coin toss/slot machine roll etc. has - typically it's a high and unusually precise percentage, like e.g. 95.1681%.

The scam in is advertising, that emphasizes how much you can potentially win, even though obviously on average the house takes those few percent each time.

[0] A term they like to use to describe themselves.