Giving some data could make good sense. But giving away unlimited data makes no sense at all. Every mast has a limited capacity and the more data that people use at the same time, the slower that data arrives.
Unlimited data would encourage people to waste it, making it super slow for everybody even if they were using only reasonable amounts of data.
Some of us remember the days when giffgaff tried selling an unlimited goodybag and it being announced that 1% of members were hogging more than 90% of the available data bandwidth. Which is why giffgaff had to stop selling an unlimited data goodybag.