PS3 was the cheapest BD player upon release and stayed that way for a while. On top of that, it got regular firmware updates to make it compliant with the constantly emerging BD standards while dedicated BD players had sporadic updates, if they got any at all. Some argue that dedicated players produce a better picture quality and sound than the PS3, but they cost more and you don't get a games console with them. You can find BD players a lot cheaper than a PS3 now, so it's not quite the same anymore, but for a quite a while at least, the PS3 was the better option.