How is this package different to any other package?

If you sign up in the store Unicom will ask for a large deposit. They know you will not use that much credit and they consider it pure profit.

The data should be good for 1 month and the sim for 6 months. If your lucky this guy has a special deal with Unicom and the data is valid for 6 months. Definitely no such deal for tourist who walk in to a Unicom store.