I would recommend not to use this all the time if you want to master blending in photoshop. ) Therefore I personally find it is helping me learn to blend in Photoshop via the aforementioned technique. (The most common way of painting in Photoshop. I always avoided the tool for blending but I find that with this custom brush and the Smudge Tool, not only is it easier for me to see the difference between two tones when blending, it also makes it easier for me to judge a nice blending job when doing it the other way of layering and colour picking. There are creative ways to use this tool and it's in there for a reason.

I know what you're thinking, SMUDGE TOOL!? There might be many reasons why you would want a similar brush in photoshop, I for one wanted it because it's easier and Paint Tool SAI still doesn't like my computer. So a lot of people, including myself, freakin' love the Water Brush in Paint Tool SAI.