The only significant benefit over traditional operating systems/network services is it's designed to work on flaky hardware and networks. The only use cases i've found for decentralized distributed networks of application services (other than obscure stuff like parallel processing of large datasets) is when you have no guarantees of availability. As far as "scaling", you don't need coreOS to build a scalable network (and i've seen no performance benchmarks of coreOS running on thousands of machines at a time, so I have no idea how well it scales)