At one time, it certainly had a point, in that it was a way to passively amplify an instrument that was quickly buried by other instruments. Of course now we can simply amplify for relatively little cost, but the sound of one can serve to authenticate a "period" piece, not unlike a banjo ukulele. Both are probably unnecessary with amplification, but both add quite a bit to the tonal palette, especially if you like the Hot Jazz stuff that was being played on the mainland in the 20's and 30's.