Comment by pityJuke

The situation is almost always “weird networking.” A WiFi hotspot too new for a device you have. Captive authentication you can’t solve on your e-reader (this was the case for me at college). Or, as I’m using one right now, as a simple booster (with a battery plugged in).

Given that this has been available on Android for years, I do not consider it an overly difficult feature for Apple to implement.