Carlo's first foray into the egrid was so that we could do as Bots suggested and make different areas with different physical constants.
The idea was revisited due to the new ideas of metabolism so that we can have different areas of localized abundence of potential metabolites.
Also I wanted to be able to make physical barriers without using the traditional "wall" method so that we can get some kind of niches for specialization.
Loads of ideas. Very little actually done about it.