I like footnotes.
They represent a certain amount of nonlinearity in my prose. If I have a point which is relevant, but doesn’t fit anywhere in the flow of thought in the paper, I can separate it out from the text, to be perused at the reader’s leisure.
On the other hand, if I have a point which doesn’t fit into the flow, it begs the question of whether it really is relevant, and if so, whether it should fit into the flow after all. Therefore, I tend to find myself either rewriting footnotes into the main prose or just outright deleting them. On occasion, I have even found myself (on this blog) turning footnotes into separate posts, or even replacing the original post with the footnote, because it was far more interesting.
I like footnotes because they provide a convenient holding place for ideas before they go elsewhere. Not to say that I don’t enjoy a good footnote — simply that I don’t often find a good reason to keep them around beyond the draft stage.