Fitness trackers have issues with people being very excited to get them (great for sales!) but losing interest in using them quickly over time (boo for repeat sales, word of mouth, etc) The way Fitbit, etc usually try to improve longevity is by building community and ways for people to compete. This make sense because people who have accountability tend to stick with workouts better.
This is more of a motivational band than a tracker and the motivation is all coming internally. Having a the QR code adds a bit of tracking and the prizes can provide motivation, but how can we promote use over time? Will the prizes be attainable enough and are there levels users can work through? Is there a way for them to chart their own goals?
I love this concept. I hope that when you say "apprentice/internship" you intend for the participants to be paid for their work. While it is a great learning experience, there will be many young people unable to afford to participate if they do not get paid. (Additionally, if they are doing real work, they are legally required to be paid.) Perhaps the companies provide a stipend?