Obviously, this will not work in every situation, but I imagine could be useful for a lot of simple things or emergencies (ok, I realize that you may not have the time to sit and click through a bunch of symptoms if it's a life or death situation - but they will probably already try to figure out what's wrong with you at that point anyway). Also, many hospitals often have some doctors that speak English, or a translator available, though the times/days may vary, so this may not be necessary in those cases (but still handy and potentially speeds up the process for them).
Speaking from experience, something like this would have come in extremely handy my first year, when all I could do was point to the areas that hurt and say "painful" in Japanese. Of course, I survived, and practice does make perfect, but for things like I mentioned above, this may prove useful. I've included screen shots below.
And no, I'm not saying you shouldn't try to learn Japanese either - but hey, you can even choose "simple Japanese" as a language option to practice.
The site can be found here.
You can also read the original article on The Japan Times, here.