Still seems profitable quite quickly if it actually did give a 5% productivity gain. Keep in mind that the ratio of devices per person is more likely to be abo

Still seems profitable quite quickly if it actually did give a 5% productivity gain. Keep in mind that the ratio of devices per person is more likely to be about 1:3 rather than 1:1. A device can work much more hours per week than the average human, and it only needs to stop for a battery recharge.