I do tend to agree that a set aside environment for biological filtration is a good idea for several reasons. I think the "no bio needed" argument came about as an answer to the "well how much is the minimum?" question. Obviously the minimum needed would have a lot to do with what you are keeping. The original point was not to advocate no bio at all, but to put some reality in people's minds when designing their filters and suggest that large bio towers are not generally required, so unless you want to build them for the hell of it, there's really not much point.