What is Data coverage?
Data coverage refers to the location in which you can receive and transmit data from your mobile device.
You will not be connected to the online world if you are in an area with no data coverage. This is important when tracking your IoT devices, for example.
What is the difference between Data Coverage and Mobile Signal?
If you send a message and a person does not receive it because they do not have a data signal, the fallback option ensures SMS delivery by pushing SMS to Telecom Operators bypassing the servers. In that way, it is guaranteed that messages are not delayed e.g. because of server issues.