Life appearing independently on two different planets in the same solar system dramatically jacks up the odds that life appeared somewhere else in a universe made up of 100 billion galaxies, each of which contains 100 billion star systems.

If we find life elsewhere in our solar system, my money is on it sharing a common ancestor with life on Earth. We already know that rocks ejected by meteorite impacts can wind up on another planet. It's not too much of a stretch to imagine some spores coming along for the ride.

The converse is true as well. If life is not found in an environment that is hospitable to it, it dramatically reduces the odds that life exists anywhere else.