No encryption on PS2 discs

I found out the interesting fact that PS2 (and PSX) discs don't contain any data encryption. In contrast Xbox and Gamecube discs do making them harder to copy straight from an original disc.

Maybe this is one of the reasons for the true popularity of the Playstation to date. Being able to copy game discs using standard software, instead of the need for special decrypting or ripping kits, means that the only obstacle is then bypassing the firmware copy protection in the actual system.