I think that I would need a description of the requirement or use case you're looking to meet to fully answer your question.
I can at least tell you that there is a DXL client installed on ePO servers by default that can be used by ePO extensions to connect to the fabric. Due to sharing/performance concerns, it is considered best practice to use this client as sparingly as possible.
My use-case is that I want to get a list of tags from ePO using a DXL request.
The Python ePO Service example takes a DXL request and executes it using the ePO REST WebAPI. It would be preferable to use DXL straight to ePO instead of having to bridge it through the ePO REST WebAPI.
At present, ePO itself does not provide a DXL service through its DXL client. This means that making requests to ePO entirely through DXL messages is not currently available.
As you pointed out, the Python ePO Service example provides access to the ePO REST WebAPI as a method to access ePO information from a DXL client. This is currently the best solution available for this functionality.