We have a showcase playlist with some of the games that are using Playmaker.
https://www.youtube.com/playlist?list=PLFXYYxmSM-GeI_L78YN0hBgUrzKjXjPYeMost people tend to use Playmaker as an tool to help designers or to design systems that lend themselves to benefit from the FSM structure Playmaker offers. It so happens that practically everything can be broken into an FSM structure logically though, so its incredibly flexible.
You can create anything from the logic for a light switch all the way to a physics driven VR spaceship game. Generally, you'll be using assets from the asset store and 3rd party tools to accomplish complex low level tasks and as your core game features as Playmaker is not a tool that is expected to allow you to make Minecraft's voxel engine on top of Unity.
Plenty of people have made entire titles in Playmaker but asking if you can make Skyrim or Minecraft in Playmaker is a a silly question. Making Skyrim would be near-impossible for a company with less than 50 people on it full time regardless of the tools. Sandbox games using Playmaker? Sure, The Forest uses it, but the scale and scope needs to be realistic.
Since you already have it, I would suggest just jumping in and experimenting. We have nearly 100 tutorials on the YouTube channel that would definitely help clarify how Playmaker can fit into your workflow.