Making philosophy useful has implications that go beyond the actual uses. Being useful is one of the best ways to ensure that you aren't fooling yourself.
That reminds me … My reaction to fractal geometry was that it was evidence that the more abstract, apparently irrelevant, parts of mathematics were real. (You mean we can actually do something with this?) It reminded me of the scene in The Incomplete Enchanter when Harold Shea realized that he was a warlock.