As Bitcoin gets more attention, more online casino operators would not want to miss the opportunity to tap the crypto gaming market. Existing operators that cater to only fiat-money players would consider accepting Bitcoin, while new brands in iGaming would launch as crypto-friendly casino and sports betting sites, for instance. Gaming dApps, for instance, may also get the boost they need to launch and get a strong following and support from the community.
Halving doesn't have a direct effect on how crypto-gambling sites will get a strong support from the community. For example, even those sites that only support fiat will consider crypto, specifically bitcoin, as one of their payment method, there is no assurance that they will attract more crypto-users to use their sites.
The competition of crypto-gambling sites today is so tough that even site owners spend lots of money on marketing, climbing to one of the best is a challenge.
In general, whether there is halving or not, the crypto-gambling activity will always grow on its usual process.