Just to add something about bluetooth calls.
Sellers deliberately not saying clearly nothing about calls via bluetooth. They just say it can make calls, not saying “only with SIM card”.
This is copy/paste from gearbest:
Bluetooth calling: Phonebook
Messaging: Message checking
Health tracker: Heart rate monitor,Pedometer
Remote control function: Remote music
Notification type: Facebook
Other function: Alarm,Barometer,GPS,WiFi
I would NEVER bought any watch which is incapable of doing such basic thing like receiveing or calling via BT.
IMHO, that is fraud.