Noiseware occasionally improves your photos (photo samples)
While it doesn't provide a dramatic improvement if you only view photos on your phone, there are cases where it might be worth the three bucks.
You can tell the difference
If you look at a really noisy shot like this crop, at 100 percent, on your computer, you can see that Noiseware does a pretty good job cleaning up the artifacts, even simply using the default settings. The out-of-focus areas do lose some detail becase of excessive smoothing, but there's only so much that can be done with image noise. This isn't TV.
Not much to see here
When looking at the photos scaled down, though, the effect is far less dramatic.
A moot case
When viewed on the phone, there's even less of visible difference. (These are zoomed-in screen captures that are roughly the same size as viewed onscreen.)
Skin softener
The one interesting by-product of the software is that it acts like a beautifier for skin. You can see how much smoothing it does.
Phone portrait
The smoothing that looks obvious up close does seem to make portraits look better when viewed on the phone because you don't really miss the detail and it evens out the skin tones.
Does improve the noise
I brightened this up in Snapseed, which brought out some of the noise, which Noiseware then fixed well.
What's the difference?
The original photo was dark, and bringing up the exposure added the noise shown in the previous image. However, while the exposure-adjusted version looks significantly different, you don't really see the affect of the noise reduction unless you're viewing it at full size. (Note that I couldn't exactly preserve the exposure.)