And it is randomness that gives gamblers hopes to win. Casinos stay profitable not because of randomness but rather in spite of it. When you bet long enough, randomness gets removed from the equation entirely. And what remains, as you might have already guessed, is called house edge. Randomness can override the house edge but not for long, so technically it is against the casino. The latter just uses it to lure gamblers into believing that they can win, and they can in fact if they are lucky to conquer the odds and wise to keep their wins
Randomness is what protects a casino against a smart player. Something that is not random, i.e. predictable with even the slightest chance of sustainable success, will be eventually exploited (think blackjack card counters)
Randomness doesn't protect the casino
On the contrary, it is randomness in and by itself that allows a smart player to override the house edge and win more or less consistently (as first explained and then proved in
this thread). If it were not for randomness, which is the opposite of the house edge in a sense, you couldn't exploit the variance in bet outcomes (which is how randomness reveals itself in real life) and ultimately beat the house
And that's also the reason why so many casinos are limiting betting speeds as well as minimum bets (more specifically, with doges). A smart and experienced player knows how to use the power of randomness against the house. It is through statistical outliers, which are possible only because the bets (rolls in case of dice) are random. If they were not random, there couldn't be outliers, and thus there'd be no chance to overcome the house edge