This was expected to a degree. WISE 0855 is just at the right temperature for water or ice clouds to form, so it would almost have been a surprise if those clouds weren't there. Still, it's an important breakthrough. Now that scientists have a way to find water clouds beyond the Solar System, they could use their technique to determine the prevalence of water vapor in space using brown dwarves as benchmarks. It's not the same as finding clouds around an exoplanet, but it's a start.