One advantage of crude models is that we know they are crude and will not try to read too much from them. With more sophisticated models,
… there is an awful temptation to squeeze the lemon until it is dry and to present a picture of the future which through its very precision and verisimilitude carries conviction. Yet a man who uses an imaginary map, thinking it is a true one, is like to be worse off than someone with no map at all; for he will fail to inquire whenever he can, to observe every detail on his way, and to search continuously with all his senses and all his intelligence for indications of where he should go.
From Small is Beautiful by E. F. Schumacher.
Obviously crude models are not always better. But I like to have some evidence that a complex model is worthwhile before I invest too much effort in it. And I’m well aware of forces that reward complexity for its own sake.
Update (15 May 2015): From Simple Rules by Donald Sull and Kathleen M. Eisenhardt:
We often assume that the best way to make a decision is by considering all the factors that might influence our choice and weighing their relative importance. Psychologists have found, however, that people tend to overweigh peripheral variables at the expense of critical ones when they try to take all factors into account. … Simple rules minimize the risk of overweighing peripheral considerations by focusing on the criteria most critical for making good decisions.