Workflow, Workflows, Workspace, and State Machine-- what is the difference?
There are also content moderation module which aims to define content states. 
From my understanding, core Workflows is API and UI to utilize the moderation states and transition. I am not sure if core Workflows could work with states machine, but logically it should.

Core Workflows and contributed core Workflow must be similar in their general goal, but provides different widgets, and architecture. 

It is very interesting question and I would be happy to hear some clarification.