LTE-M could be used for a number of use cases across several industries.  The long battery life is ideal for devices expected to be in use for a long time.  The better coverage helps for devices that are behind thick walls, deep in basements, or subterranean.  Lower cost of modules enables mass deployment of devices.  Licensed spectrum and SIM cards ensure carrier-grade security.  Mobility allows for cell tower handoff.   

Metering (Smart Cities), Smart Buildings, Asset Tracking, Asset Monitoring, Retail, Healthcare, 

Consumer wearables are all use cases that would benefit from LTE-M.