@Dannyckm, welcome! Yes, children working together can improve their efficiency. But one child working alone must also be able to succeed. Your app needs to show that it works well for one child working alone. If it works even better for groups of children working together, that's great, but if it ONLY works for groups then that's unacceptable.
A child working alone doesn't mean a single person out alone in the forest. In some situations children may have more time to use their tablets at home, where they may be out of Bluetooth or WiFi range of other children. Don't assume that a group of children will always have opportunities to work together.