at least for the "caught in a novel" version of the simulation hypothesis, you only need to start worrying once the world starts making sense in a narrative way
Given entertainment we get from fiction is tightly coupled with evolutional brain chemistry, I think it is safe to rule out "simulation for entertainment": An actor powerful enough to host our simulation would most certainly be post-biological.
Now, for a scientific simulation, the question is: What answers could such a simulation provide to make up for the loss of energy otherwise spent on occupying the universe? If conducted post universe-occupation, then what answers could it provide to a universe that knows itself?