I can't think of anything more profitable at the moment. Although I don't know in depth the income from online casinos.
However, to create an online casino, you need a lot of investment and be willing to pay for advertising and interact in a forum like this.
I don't intend to have an online casino, I'm more interested in having an e-commerce.
One of the factors that makes me believe this is that there is already a whole audience ready to play in casinos, as they are generally people who bet out of addiction, to make money (or even when they lose, they play just to pass the time). In addition to the fact that there are costs for servers, employees, online attendants, programmers and other costs, unlike physical casinos where the costs are for installations, maintenance, energy and employees and security guards...
Do they make more profit than digital banks, CEX exchanges, etc.?
Online gambling casinos are definitely making a whole lots of money, but i honestly will not agree or assume that they are making more money than the big centralized exchanges and digital banks, reason being that, centralized exchanges and digital banks are making solid profit without almost risking nothing, I mean, they charge traders for every trade that is successfully carried out, whether it's a buy or sell, and they don't even wanna know if the trader has bought the coin before and at present time selling at a loss, they will take their charge regardless, and they also charge for coin withdrawal from the exchange.
Almost same with digital banks that charge customers for every transfer to other banks networks, and also charge customers for some in app payment services like paying for light bill, buying subscription for your TV, recharging your mobile phone and so on, this monies are made without the digital bank risking anything.
But the casinos risk losing money when ever a player wins a really huge amount of money, it's true they make the money back from other gamblers who are losing, but still, money taken out is a minus, not a plus.