I think it's just more simple to create an online casino based on blockchain, cause it gives more opportunities for your users.
Yes, since it is simple to create a online gambling casino , many people are misusing it to create scam casino and run away with people money. Although it is a blessing to have online casino to play gambling but at the same time, i have seen a lot of people complaining about it as many sites owners develop online casino to get people money and also do not provide probably fair games.
There are a lot of casinos out there that have took advantage of blockchain popularity and reputation just to attract people and steal their money but this doesn't mean blockchain is not a great thing for gambling industry. It's the people who created those websites and stole that money we should blame for this. There are lots of blockchain casinos out there that are very popular and trusted, like Stake and Primedice and they also offer provably fair. You have a lot of options to choose from and you should be happy that you have acces to this technology.