No, a lot of WiFi IoT devices create a hotspot that your phone connects to. It's hacky as hell - you have to do the connection manually on iOS (unless it uses Homekit), and some devices only support one WiFi connection so they have to disconnect from your phone before attempting to connect to your network so you get zero feedback.

But it saves $2 on the BOM.

most wifi SoC support peer-to-peer over wifi, now-a-days you don't really need bluetooth.