There's no reason to be using the installers as the morphs are now in zips - the only catch is that they contain a Content folder before you get to the vital folders, all you want to merge with your Poser library are the folders inside the Content folder.

For those of us who have backup copies of our files, we ARE still using those installers, so this is universally true only if the packages have been re-downloaded from DAZ since the switchover.  I have backups of all my original files and have no reason to re-download.