WiFi uses near 10x the power Bluetooth does when active (and that’s before factoring in BLE which cuts that down in half). WiFi also has access to the much less crowded 5GHz band.
IIRC WiFi is also a much simpler protocol, it’s just a data channel (its aim being to replace LAN cables).
Plus in order to support cheap and specialised devices Bluetooth supports all sorts of profiles and applications. This makes the devices simpler, and means all the configuration can be automated to pairing, but it makes the generic hosts a lot more complicated.