correct you are!...i dont have one in my car yet but i will by the end of summer...i'm guessing they are popular for the following reasons...
1. bolt into 88-91 civic and crx's with the factory engine mounts
2. if you have an hf or si the harness should plug up to everything with modification on one wire somewhere...changing the dx wiring harness is quite simple too...or so i've heard
3. almost as much horsepower as a b18 swap will yield but not as much torque...for much cheaper

...there are probly more reasons people do it...everyone else let this guy know why you think the zc's are so popular...maybe somethin i said about the wiring harness stuff isn't all the way true...just going by write-ups i've read...let me know if i was wrong...later