BLE (Bluetooth) trackers have been great for "I lost it in my house" or "I can't remember where I saw it last" ... The ones with a distance warning are excellent when taking the family to the theme park, or setting off an audible "alarm" to locate that parked stroller when some (helpful?) person moved it for you.

Although, I have to agree that GPS is better for your kids that walk to school alone or your valuable items. Ideally one that can be reasonably "hidden" on the person/property to be tracked so that thieves/kidnappers are unlikely to detect it.

The concept of "Crowdsource GPS" with BLE devices has interesting potential for finding things in areas with a lot of subscribers, however to be truly effective the "crowd" would either all have to use the same device or the source code would have to be in some way universal.

Combining block-chain dapp with BLE in populated areas could be an excellent stop-gap to the "economical" short range positioning of things and people lost.