IMO that's even more of a reason for this. If the world continues normally, then old hard drives and CDs can just be copied onto new ones over and over again. I

IMO that's even more of a reason for this. If the world continues normally, then old hard drives and CDs can just be copied onto new ones over and over again. If something ever happens, then everything will be lost. With this, we could preserve a huge amount of the world's knowledge forever. However I see what they are trying to say. 300M years is a lot, when even 100 years would be great compared to current storage systems. And on that time scale, the rate of bit rot is less important than other factors.