Most people that are not connected do not see a value on it. They think it won't help them in any way in their lives, that's a rich kid thing. The idea of the project I believe is to provide a free taste of limited functionality, to open that door to new opportunities. Then decide whether the value is worth it or not, and purchase an internet plan as his/her requirements dictate. It's a sort of "internet" literacy that wants to be spread. Feel free to actually check what the internet.org package offers, and imagine how it can help someone appreciate the value of being connected.
Right now due to lack of knowledge people without any access to internet have no idea how their crippling their own future, and their children's future. I believe the idea of internet.org is to provide some sort of basic free services that may help people decide whether full internet connectivity is for them or not, and try to change the "that's a thing only for rich/tech/lazy/young people" mentality that may prevail in rural areas for example.
In full disclosure I worked for fb for 1.5 years and haven't worked for them for half a year. These are my personal opinions .