Mostly, this is in instances where high and reliable bandwidth is required, such as gaming, streaming, or situations where the Wi-Fi ... built-in Ethernet port and will need such an adapter.

While we are used to USB WiFi adapters ... Bluetooth, up to BLE5, either over an extra UART channel or the same SDIO/SPI channel; you can even get BT audio over I2S. If you have an SPI/SDIO port ...