Mainly attics. Anywhere that can freeze. I hate installing dry systems. They are a nightmare compared to wet.I wouldn't expect it to be dry (or chemical, which is what you're referring to) because of the first cost and a wet system would function just fine. I could be wrong.
I am familiar with sprinkler systems in ~100 buildings that I oversee and do design work for, as a frame of reference. Very few are dry systems - mostly parking ramps and a few very highly sensitive areas. Some are chemical systems - such as helicopter landing pads and datacenters.