Not at all. In most embedded devices, the point of the software on the device is some specific function which is something more than “the kernel is running” or

Not at all. In most embedded devices, the point of the software on the device is some specific function which is something more than “the kernel is running” or “the kernel is scheduling the zero-io watchdog process.” You want to actually pick up the case where the kernel is up but, for example, your process is all but dead because your storage driver has wedged. The goal is to prove forward progress and the best way to do that is to come as close to proving that your userplane SW is actually working and not dead, or worse, half dead.