They probably expect the signage to change a lot and don’t want a hardware failure when they do it too much, or didn’t use an external drive in this case and the SD card failed because they wrote to it too much (which would happen eventually anyway).
They probably expect the signage to change a lot and don’t want a hardware failure when they do it too much, or didn’t use an external drive in this case and the SD card failed because they wrote to it too much (which would happen eventually anyway).