If you have a stateless app, or state that can be deployed in multiple locations, then these are good solutions compared to doing it yourself and are relatively easier to deal with than the IaaS options of the clouds. Having it built into the CDN layer only helps with performance.
At StackPath our definition of Edge is basically being as close as possible to the eyeballs aka users. Think of it as the front door to the internet.
Today our Edge expands across major IX's around the world and that's just the beginning. 5G is approaching us quickly along with container data centers.
The way we built our orchestration system it can deploy and manage workloads anywhere. In the future, that will include 5G container data centers which gets workloads even closer to things like self-driving cars, smart cities, IoT devices, <insert your idea here>.
Oh, please. If you really need those last few milliseconds of lag reduced, you need local computation. If you don't, an AWS datacenter on the same continent is probably good enough.
Is it worth the hassle? All you're saving is latency in the backbone between the point of presence and your home data center. Does this beat directing requests to the nearest AWS region? As long as you're in roughly the right hemisphere and time zone, you're probably close enough.