These are excellent devices for anyone managing insulin dosing or for athletes in training. The downside for many is cost; over $10 a day, less with insurance, (Blue Cross pays half). Also, (locally at least), they're not approved for use in hospitals. One could argue that this is because hospitals would no longer be able to charge to poke their insulin deficient patients 10 times a day.
The Libre also requires the wearer to purposefully interact with the device and their smartphone. Not a big deal for most but for the elderly who may live alone or have issues with technology and/or mental capacity, it will prove to be less useful. A Libre which automatically takes readings will greatly expand use in this area.