SteamOS is Valve’s Linux-based operating system. It features a seamless user experience optimized for gaming, while retaining access to the power and flexibility of a PC, and plays tens of thousands of games on Steam. SteamOS officially ships on Steam Deck, and will soon ship with certain Legion Go S models. We’re currently working on adding support for more devices.
On a handheld? Probably depends how much you use it outside game mode and what you do with it.
On a desktop? No. It’s not intended to be a fully functional desktop OS.