Filtering performance on Poisson noise with quadratic data-fidelity
For large intensities / large "bins", i.e. "areas for which events are counted and accumulated", Poisson processes lead to nearly Gaussian distributed individual values -- basically, without trying to derive this, I think that's  the application of the CLT on a lot of realization of a point process.

EDIT: Shameless plug: I really really like the wikipedia page on "Relationships among probability distributions; notice the arrow between the Poisson and the normal distribution: