In the old days, 1990's, :p  ...  Mac's could not work with zips (actually they could, but you had to have a special app to open them).  Mac files were "zipped" via .sit files (which would not work on a PC lol)

OS X DAZ installers will install the files for you, or you can opt for a custom install and have them go to whatever folder you want. Most of the stuff you buy from merchants as zip files can be unzipped but you have to deal with them as previously mentioned above.

Now here's some fun stuff for older Mac users. If you previously bought DAZ products under OS 9 and are running a new Mac that does not support the older Mac systems, you will not be able to even open the old DAZ installers.  Yeah you have to go run the installer on an older Mac and then copy the files over to the new Mac. Ok, some of the more popular files have had their installers updated by DAZ to work in OS X, but not all of them.