Scala players are standard x86 machines, which means the hardware can outlive the platform it was bought for. ScreenlyOS installs onto them directly, so a fleet already mounted behind displays can keep working under Screenly instead of being replaced. Support is per model, and Supported models shows where each one stands.
That matters most where the players are hard to reach. Swapping the software is a visit with a USB stick. Swapping the hardware is a visit with a ladder, a new device, and a mount that may not fit.