Significant — you’d need to either get the old Linux build working (not an easy task today) or you can install it on Windows, copy the files over, and run it via Proton (but you’d need to manually add the registry key with your CD key to the Proton prefix’s registry).

Three thoughts:

• Valve doesn’t use physical media, so there isn’t a need to enforce DRM at the hardware level
• the Deck itself is sold at a small profit regardless of the configuration, so there’s no benefit to pushing users to higher-price configurations
• Valve enforces its DRM in software via the OS

The biggest reasons to lock down hardware aren’t really there on the Deck. On top of that, it benefits Valve to have other devices running their storefront, so using off-the-shelf parts when possible makes it easier for others to use the Deck as a template.