Just from my own experience, many flatpak apps such as Steam, VSCode, or Kdenlive have a lot of issues, and many other flatpaks are maintained by third parties with poor quality control. This isn’t Silverblue/Kinoite’s fault, but it is still an issue that affects it. For certain machines where drivers aren’t included by default, it requires a lot more troubleshooting to install them compared to Linux Mint’s driver manager, or even just copying a few commands from the internet on a distro like Fedora.
It’s more of a historical problem, and I’ve always been able to solve it. Not everyone has the time or patience that I do though, especially when it involves changing permissions with flatseal. Overall though, the fedora atomic versions are solid, and it’s ok for beginners. It just adds a slight bit of complexity plus less resources for troubleshooting than linux mint or ubuntu.