Bluetooth is a means by which tablets can wirelessly communicate with other devices, such as other tablets, smartphones or additional items such as Bluetooth speakers. WiFi, another wireless communication method, is primarily used for connecting to the internet. Bluetooth is not essential, but is it a useful extra.
The Dragon Touch X10 Kids comes with Bluetooth 4.0 as standard. However, if Bluetooth is not actively being used, it can be a good idea to turn it off so that the battery will last longer, especially if the tablet is away from a source of power.