>it is quite clear who will benefit: those in power
I think it's more likely that you want to detect a person so you don't hit them with a car than trying to hit them with a drone missile. Detecting cancer with CV, and other improvements to diagnostics also save lives. If you could be working on these technologies and stop, your decision could cost lives.
The same neural network can be trained for both problems. Advances in medical image neural networks translate to advances in people detecting neural networks.
Of course, they are not directly used without changing the training data, etc. However, if we look at the big picture to make a general statement, then the advances brought by Computer Vision on natural images often help push research on medical images forward, albeit with a year (or two) of delay. One such example is U-Net (https://en.wikipedia.org/wiki/U-Net).
I think it's more likely that you want to detect a person so you don't hit them with a car than trying to hit them with a drone missile. Detecting cancer with CV, and other improvements to diagnostics also save lives. If you could be working on these technologies and stop, your decision could cost lives.