Only had the data for 24 hours
So don't look for any certainties, yet. But liquid bodies a) fit the most likely hypothesis - that photochemistry in the atmosphere would cause things to settle out, so that some mechanism must replenish what was in that huge atmosphere = cycling liquid/gas, b) fit the need for some kind of fluid to provide erosion to hide the craters, c) explain several different things that we see on the pix.