WaaS is heading for non carrier approval. The first release of the OS should come with device specific firmware. After that, Waas takes the ball. Waas neans that Microsoft will be able to update the OS excluding the radio stack, since it is not necessary to be updated (and approved/blocked by carriers) all the time. So, Microsoft makes another huge step ahead, by giving us updates that will be OTA at any time
Just a speculation though, there will be firmware updates during the year, but, WaaS will stop the winning about non-frequent updates and complaints like "MS has abandoned us" and other bull...