Since it's for business usage, i would make these suggestions.
1. Do some research on TEE (trusted execution environment). It's feature provided by CPU or SoC to manage sensitive data more securely, although some people distrust it due to various reason (e.g. consider Intel ME as a backdoor or security issue).
2. Unencrypted swapfile bring security concern, since sensitive data may be stored there temporarily.

Although i agree with @odolvlobo to simply have few casino's wallet and database which track user's balance along with it's changes, since your user currently doesn't have access to their private key anyway.