- Nomad is a more general type of workload scheduler. What I mean with "general" is that you can schedule pretty much anything over a bunch of hosts - not just containers e.g you have a JRE on the node? Just schedule your jar. Execute a raw shell command? Not a problem.

- Batch jobs with parameters? Just send it to the "dispatch" endpoint with parameters and an optional payload. Often can replace "serverless" and sometimes work queues.

- Consul is a "general purpose" service discovery (dns & distributed K/V) that can span over all your services, not just k8s ones (for this very reason Hashicorp have built a k8s -> consul services sync tool: it is often needed!)

You include consul agent with a service definition in roles on your ansible/salt/puppet managed VM's. They can be included in the mesh, and SD works seamlessly between hosts and containers.

- The consul connect (mesh) feature with envoy is much more comprehensible than istio.

I use to say that nomad + consul is more in-line with the "unix philosophy". You have these two binaries that do what they do independently, but they can be hooked together if you would like to use distributed K/V and service discovery for your scheduled workload. Add Vault to that - which often is used without consul & nomad, but integrates as well.

They can all be easily integrated with through well defined rest API's and do not have to be consumed as a big black box.

K8s is all or nothing.