Optimize POE performance by defragmenting content.ggpk and by creating another ggpk file?

Hi,
I saw one player said he has a 30GB content.GGPK file and he created a folder "BAK" and move content.ggpk file to that folder. After that, he launch POE again and POE installer will create a new content.ggpk and its size is only 16,385 KB(Yes, 16MB). I ask him, "are you sure you can run POE with 16MB content.ggpk" and he say Yes.
Also, I find there is a ggpk_defragment.rb(wrote in ruby language) and it can reduce 30GB content.ggpk file to 20GB.
https://gist.github.com/Zoxc/2393192

Both methods will increase performance according what they say. Is this true? What's going on? Why does GGG make this function when deployment?