The liquid water is an extremely salty brine, that flows seasonally as temperatures permit - just below the surface on the slopes of mountains, canyons and craters:https://www.nasa.gov/press-release/nasa ... day-s-mars
This is a significant find, since it opens the possibility that life - if it ever existed on Mars - may have evolved to survive under these extreme conditions, and may even exist there to this day.
If life does exist on Mars today, the next question will be: does it share a common origin with life on Earth? Or did an asteroid impact eject fragments from one planet and bring them to the other, sowing microscopic life between the two worlds? Either finding would be significant, but in terms of its cosmic significance finding two independent origins of life - one on Earth and a separate one on Mars - would drive the statistics in favor of a multitude of independent life sources across every habitable corner of the galaxy.
So yes, finding liquid water on the surface or near-surface of Mars today is a significant finding.