It should be beneficial for the casino to try to identify errors/problems in the operation of the website or casino software. Because the financial security and profit of the casino directly depend on this. Any sane casino will offer rewards for finding bugs for white-hat hackers and ordinary users, or even organize hackathons.
For sure before a casino is launched, there is what operators always do and that is make sure to test all the system of the casino systems to make sure they are bug-free because any casino that has a bug problem will likely not succeed in terms of revenue generations which is an integral part of the casino operation.
Some casinos even give incentives to expect bug hunters to run several private hunts on their systems before the site goes live, The majority of the casinos that crashed along the way are all doing so because of a lack of proper bug tests and exploitation of the system via the bug or other system failures.
Generally, it's not only before the launch, but some platforms would have a bug bounty for a pretty long time when they start their platform so that users that find the bugs report it to them to get the reward instead of trying to exploit the bugs and steal from the casino. I believe some people might try to do that instead of reporting the bugs because a lot of people think it's easy to use a bug or something in a platform and then steal from the system.
If a platform, whether it's a casino, a new cryptocurrency project, or anything in general, doesn't have a specific bug bounty, you will barely get anything from them if you report a bug because they will say that unfortunately they don't have a bug bounty right now and they might compensate you later for it but you won't get anything later.