I wasn't sure I really needed this one, seemed to be designed to boost the level of the Triangle waveform from the VCO and not much else!
Having owned one a while now I think it's a great module to add to your AE - boosting any lower volume signal, pushing stuff into distortion ( ) and, most often for me, just a level/mix adjuster so I don't knock out any of the main patch wires out! It's getting a little less use on the latter front since I added the 4ATTMIXFADER module, but an excellent utility module to have - quite good on bass,
I think you summed it up quite accurately. I thought it would be overkill to have the signal amp and the quad booster modules but they are 2 very different modules with each their purpose. The booster is adding color to the signal whereas the signal amp is very neutral, it just makes stuff louder, sure you can push signals to distortion which is nice but it does not color the sound. A real bread and butter module.
One thing I like to do in order to use it as a distortion is to route the output of the first channel into the input of the second one, and only slightly overdrive each channel. This sounds better than pushing the gain on a single channel.