As the borders between various disciplines are slowly vanishing with the advent of interdisciplinary areas like Biophysics, Environmental and climate studies, and Complex systems, how do we deal with such questions in Physics SE? Usually, I try to answer questions that can be reasonably explained with physics. Others I vote to close or ask to migrate to Biology or the sister sites. But how much exactly is "reasonable" is a matter of debate. I have two concerns that need to be addressed.
To what extent can we create new and new interdisciplinary SEs whenever a new field emerges? Would that be sustainable in the long run?
What are the real reasons why there should be separate SE sites when the disciplines they address themselves are getting more and more interconnected?