They make sense because they are directly under your fingers, so you don't have to move them all the way over to the arrow keys and back just to move around.
jkl; would make more sense, that's the only oddity.
They should be respecting their directions, like the arrow keys do. Think UHJK or IJKL. Plus they would need nubs or similar to make them stand out a bit.
If you search for "oldest computer keyboards" in your favorite image search utility, you'll notice that many keyboards there don't have arrows at all. I did not find any keyboards with the arrows on the left side, although it wouldn't surprise me.
jkl; would make more sense, that's the only oddity.