You have to realize its not really made only for africans and third world countries. they are testing it in new zealand with farmers living in very remote areas, so they can get connected to the outside.
I live in a forest in Germany, not even far at all from the city (15 minutes drive) but my internet DL speed is 40kb/s max, so its really something that can be used anywhere, as at my home it would be multiple thousands of euros to get a fiberglass cable for proper internet in my house.
And for the problem that they still need PCs, it is possible to put together a linux PC for ridiculously cheap, even if i dont think its what they are directly aiming at with this.
To clear it out, its not world wide wifi, but i could see my house with one of those red things on it one day.