What difference does it make?

If you think you are real, then answer that question yourself. :)

No, that is really the question.
In many definitions of theories of the Simulation sort, there isn't any difference.

You must be making a conclusion that in one, you are real, and the other not.

I cannot tell what your assumptions are falling on either side of the line.

I would say that this reality IS a simulation
That this reality is printed, like an electron beam prints the picture on the TV
several trillion times a second.
And between each one of those, we don't exist.
That at any moment, this whole thing could end, like a giant power outage ends an MMO,
we could all wake up from this dream.

But that doesn't make this experience of being a human on Earth any less real.