One of the greatest advantages of Sentinel 2 is its revisit time of 5 days, if you count both satellites. Even though resolution is 10 m for RGB, it's true RGB, not some pan-sharpened soup like in the case of Landsat. It's good enough to track e.g. construction works. Or environmental matters like water bodies, deforestation etc. Compared to other free imagery 5 days is real-time ;)