Not niche, but surely exotic: NixOS, a distribution that is configured via a purely functional language. There is no such thing as installing or uninstalling packages, you add or remove things from your configuration and then simply apply that configuration.
You mean poker without real money? Because there are a lot of gambling sites, I would believe that some of them also offer poker. But please, there are better things to do with your money. You could donate it for example.
There are people who game on Linux just as there are people using Windows or Mac for IT infrastructure.
Arguably, some games support Linux, but why would anyone ever trust a closed-source private product with security, if an internationally recognised open source solution exists?
At least in Europe the year after the copyright statement has no meaning, and even the copyright statement itself is useless. Since if not stated otherwise, no rights are granted by default.
It's not a photo, it's an AI-generated image. Also, it is not clear if it is serious or a joke. Looks more serious to me.