The basic goal is to give something better that a pay slip. The job is a bit mind numbing, and while you can listen to music is very isolating. Effectively, at the moment it is impossible to feel like it is more than just a pay slip and its really difficult for people to stay motivated as they feel isolated and individualistic. Imagine working in a cubicle with no one around, where your work is to data entry a slightly different piece of paper over and over for 8 hours.
Sounds like the dream job for a lot of people. Really. There are agencies that help you find staff with certain special traits that would love to do such jobs.
Why bring in something complicated like artificial and complicated gratifications to staff that doesn’t like the job (their attitude even may not change with your efforts)? Why not bring in staff that likes the job without any additional troubles?
For some people and short term it is absolutely amazing - I’ve had students and people after a bit of extra cash that love the ability to just do. What worries me is the long term - I have staff who have been doing this for 8 years who do little more than work, sleep, work. Very little ability to socialize or feel like a part of anything, and it easily leads to depression and burnout.