Cellphones are nice to have, certainly, but compared to safe piped water and electric light, they are a minor addition to quality of life. Ask anyone who has done without the latter two for extended periods of time.
The point is that the cellphone is a multiplier with which every person can improve their lives. That was true before the internet (see fishermen in Africa using phones to communicate about the best current fishing spots) and even more so now.
If you put me on a desert island with an internet-connected phone that I could recharge once a day, I'd have a far better chance of surviving [1] than if you gave me a flushing toilet or a power point in my house. Obviously there are comparisons that will fail this, but this is to underscore the spectacular catalytic influence that everyone (roughly) has in their pocket.
Our child's carer has a mom living in Zimbabwe, who has no power and running water. She used her cellphone to contact her child when she was sick, to get money, get a lift to a bigger hospital. She made her own choice on what she would buy and in this extreme case it was the smart move.
[1] Help I'm on a desert island, here is my location. How do I gather water. Is this plant edible. Is that animal dangerous. How can I build a shelter.
