The OMRON connect app needs the locations services option on your phone to be turned on in order to perform the Bluetooth low energy scans required to sync your monitors.  

Google added the locations permission requirement to alleviate concerns that Bluetooth beacons can be used to track your location without your permission during a Bluetooth low energy scan, such as the scan required to sync your monitors. By granting the OMRON connect app permission to access your location, your monitor will be able to sync, but your location won't be recorded or tracked by OMRON connect app. 

For more information about Bluetooth technology, visit the Bluetooth Special Interest Group's website at bluetooth.com. 

For details about the Google permission requirements, see Google'sAndroid 6.0 Changes document: 

https://developer.android.com/about/versions/marshmallow/android-6.0-changes.html#behavior-hardware-id