The reason that’s a big deal is that a planet needs to be in the sweet spot, temperature-wise, for there to be liquid water on its surface. And liquid water is kind of important for life.
I assume the next thing they will do is see if Hubble can find any spectrograph evidence of chlorophyll. If that happens, it will be the scientific discovery, not just of the century, but of the new Millennium.
I hope I live to see it.