This means your devices and infrastructure outside of AWS, such as IOT devices and on-premises infrastructure, can synchronize to the same highly available time

This means your devices and infrastructure outside of AWS, such as IOT devices and on-premises infrastructure, can synchronize to the same highly available time sources that were previously accessible only from within our data centers. If nothing else they can use it for all the Alexas and Kindles they sell and what not. There's no reason for them not to offer it as a public service, not necessarily nefarious. There's also no real reason for anybody else to use it as far as I can tell.