Yep for the reasons ps3hen mentoined and also for downgrading even up to latest fw and the abbility to use homebrew in case of we can decrypt the allready existing hb and fake sign them with actuall SDK's. A full dex converted console can be updated and then downgraded via special_downgrader.pup's.
Also sony changed something with the PS3GEN tool. On older versions you can't use retail selfs to gen a ISO img. Now the newer tools also accept retail signed and encrypted games. Maybe this is in case off that now also retail eboot's can be run with a generated ISO via streaming from pc or/and also as a bd-emu img.
And for the dex kernel. It can be run on retail conosole with QA flag, changed IDPS but thats still NOT a full debug console. There are still other things that need to be done.