Your Daz 3D Library contains a runtime directory, and that is probably where you are installing it.

Content from Renderosity or any other non-DAZ store will never appear in smart content in DAZ Studio. (Much of the old V4/M4 content in the DAZ Store does not have Smart Content either). You need to find the content in the content panel. For Poser content, you need to look under "Poser Formats -> My DAZ 3D Library" if that is the library you have been putting it into. Under there you will find Figures, Hair, Poses, .... Usually the hair itself is under Figures or Hair and the color presets will be under Poses or sometime Materials. Most Hair material made for Poser will work in DAZ Studio, but a few hairs may have material that do not render like the promo images. Most Poser hair will not have Iray material, but the Poser material might well auto convert ok to Iray material. If the hair material uses Poser procedural shaders, it can render badly in DS, but I have not seen much of that.