The main benefit of this setup seems to be that it provided photographic evidence for the first time, showing the interference fringes and the fact that they don't shift relative to each other. Other setups of Michelson-Morley relied on an experimenter who wrote down the results.

The odd appearance consists of the two legs of the interferometer inside vacuum chambers at right angles, mounted on some kind of contraption to isolate it from ground vibration. The original 1897 experiment was open-air on a heavy stone table floating on a cushion of oil, IIRC.