You can (or MUST) use WLAN for system updates, for example. Or if the child writes messages at home, this does not take up the data volume of the SIM card. WhatsApp does not work, but messages can be sent and received via the Xplora app. Pictures and videos can also be sent. This would then be done via WLAN. Even if the child is at a friend's house, WLAN can be used there instead of mobile data. But for system updates, Wi-Fi is absolutely necessary.

Mainly for updates. Otherwise for sending or receiving messages including pictures.