Yes, for you and me who understand what that means it's just the same, but for someone with no Linux experience is going to be very different. Googling any issue he has will direct him to alter config files or install packages, neither of which would be permanent on SteamOS, while the OS is the same the usage of it is completely different, so for a person with no Linux experience to try to use it as their daily desktop system it would be frustrating because none of the help online would apply to him.