My son bought a house recently and we installed the V3 hub and a few sensors, outlets and lights here and there. Nothing complicated but I can check the house temperature when he is away, monitor the camera in the garage, etc. We live 4 time zones apart.
I got a call in the wee hours of the morning that a water sensor had detected a leak in the crawl space. After a couple of hours we found the source, it was the water supply to the refrigerator. The leak would probably not have been detected for weeks had it not been for the sensor as the water puddled behind the fridge and then drained down the wall into the crawl space.
So ST has saved us a lot of money in additional water damage. May not be the most perfect system (yet) but it came through this time.