How to explain the complexity of biofilms and the importance of studying them to those not familiar in the field?
You could also say that biofilms offer protection to microbes, similar to the way that city dwellers are protected against weather. The deeper the microbes are within the biofilm, the more protected against e.g. antibiotics. I hope that this helps!
I also like this analogy. You can also say that different parts of the microbial population have different roles, similar to the people in a city.