The system might have strong limitations, such as:

- Riding on the hoods vs. on the drops might require some 5-10% bigger power for the same speed and the same road, but I doubt the system can identify the difference.
- Lateral wind might require important increase in power for the same speed and the same road, which might not be measured by the device (it looks that the device is influenced by the front wind only).

Overall, the inconsistency of the measurement in various conditions might be somewhere around 10-20% (or maybe more). Not so appealing...

As a benchmark: it took me 4-5 months of hard training to increase my power with 10% on an indoor trainer. If the inconsistency of the device would be 10-20%, then... it is only a toy.