Choosing the DAZ Studio instead of Poser option in the installer does not change what is installed.  It simply skips the Poser.exe search and gives the user the option to point to any folder they want.  The reason I strongly suggest having the DAZ Gen4 figures in their own folder is their morhs and add ons need to be installed to the same folder the figures are in.  Once the morphs are installed they have to be initialized, some times they may even need to re-initialized.  Having everthing for them in one folder can make it easier to find the initialization .bat file.