Is Genymotion good for gaming?

Yes, but it’s a professional Android development/testing tool first, not a gaming-focused emulator. Many games won’t work, especially on PC or Mac Intel, and Genymotion has no macros or keyboard mapping. See How to play games with Genymotion Desktop? for the compatibility list and Gamepad for controller support.

If you want to play, an Apple Mac M series device or a Genymotion SaaS cloud device gives better compatibility for some arm64 games, while PC/Mac Intel often fails to install them. For game examples and limits, the list in How to play games with Genymotion Desktop? is the best reference.