GNOME is often considered more touchscreen-friendly, while KDE Plasma provides a more traditional mouse-and-keyboard desktop experience. Since the Steam Deck has a touchscreen, what were the likely reasons for choosing KDE Plasma as SteamOS's desktop environment instead of GNOME?
4 Answers
GNOME's workflow is more opinionated. Extensions can customize it, but they may not completely change the underlying behavior, while Plasma offers extensive built-in configuration and can be made to resemble many different desktop styles. That flexibility is useful for a device with both handheld and desktop use cases.
SteamOS already has a touchscreen-oriented interface through Gaming Mode and Big Picture. Desktop Mode is mainly intended to provide a conventional computer desktop, where KDE's panels, system tray, familiar menus, and window management make sense.
The choice probably was not based only on touchscreen support. SteamOS separates its gaming interface from its desktop interface, so KDE's broad hardware support, conventional layout, customization, and familiarity may have been more valuable for desktop use than GNOME's touch-oriented design.
KDE Plasma is generally closer to the Windows layout that many PC gamers already know. That familiarity can reduce the adjustment period for people moving from Windows to SteamOS, especially when they need to manage files, launchers, settings, and applications.
GNOME can certainly be customized, but Plasma exposes more of those options directly and tends to provide a more traditional desktop setup out of the box.