The easy toggle prevents Bluetooth headphone/speaker connections without breaking everything else which uses Bluetooth.
Power consumption is extremely low – rather than trying to micromanage that, you’ll see far more savings from using low-power mode earlier or uninstall the top consuming apps.
That's... exactly what the toggle does, though? It remains barely active for things like AirDrop, but toggling it "off" turns it off in any way the average person would expect, and it definitely doesn't try to establish new connections, or even maintain existing connections, when turned "off."
Power consumption is extremely low – rather than trying to micromanage that, you’ll see far more savings from using low-power mode earlier or uninstall the top consuming apps.