> Just how useful would they be in practical terms compared to 'traditional' surveillance techniques? > they can track your location, track everything you do w

> Just how useful would they be in practical terms compared to 'traditional' surveillance techniques? > they can track your location, track everything you do with an electronic device with very little investment for anyone but the most paranoid people with impeccable opsec. You've answered your own question. The stories told by people who claim to have been in these government programs are much more about singluar events than continuous surveillance of some individual. The US discusses highly-classified subject inside of SCIFs, where no one is allowed to bring in electronics and which are frequently checked for surveillance. Imagine you had a psychic asset who could tell you everything that was discussed inside any particular SCIF when you learn through conventional means that certain people have (or are likely to have) gone inside one for a meeting.