What's the matter with mobile phone cards on the street to exchange gifts or cash them?

Mobile companies have cooperative business alliances. For example, you can provide the password at the service desk of the supermarket and convert the points into shopping vouchers. Shopping in the supermarket is costly. Or you can wash the car and deduct your corresponding points, so you can wash the car without paying cash. These businesses have contracts with Mobile, which can operate in their computer systems, deduct your points, exchange the services or goods you want, and then settle accounts with Mobile and give them money.