The lesson here is that no employee who has started a new job should ever tell any of his colleagues at the new place of work that he has any cryptocurrency and that he is into gambling. And especially not the employer. And even if at the new job his new colleagues start discussing issues of the crypto industry and gambling, then simply do not participate in this conversation or avoid direct questions on this topic.
And then such guy gets fired after probationary, because he does not fit the team. I would instead talk with colleagues about crypto and gambling, if they talk about that, but give general information, nothing that can show that I am good at them. Being silent and secretive also does not work well. As an employee, it is recommended to follow what you post or interact with in social media. A person might be a good and hardworking guy, fits well in team, but posts that he is radically against or support something, and employer can take that information as a reason to fire him.