Not important I think, because it doesn't matter whether you go for higher detail or higher resolution.
What counts is which polycount you're going for. Normally you don't want a too dense and very heavy mesh. It depends of course on where you're going to use it for.
Other than sculpting I can't think of a usage which would require a superdense mesh. For instance, don't try to run a fluid sim on a dense piece of TG2 geometry (at least, not with realflow).