Little confused between Optane Memory plus HD vs SSD plus HD

My new R7 has Optane Memory and a 2T HD. Boots fast and everything runs great. However I can still return it and get the R7 with 2T HD and SSD. I have read about both options but being I am not very PC savvy a lot of the explanations on both are over my head. I use my R7 for photo editing and video editing with large files. Also could I just add a SSD to what I already have? Any suggestions would be great.