Why is the toggle allowed at all? Presumably, sometimes we don't want apps to know where we are and record/share that to the highest bidder.

International travellers will know that some apps will alter behavior or refuse to work based on your location, if it's provided. If I use a VPN, I want the app or website to use only the IP location*, not the radio location.

If you are not actively benefitting from GPS, why let the man get a constant lock on your location? Make them suffer with cellphone tower pings.

I too keep GPS off unless I am navigating.

Increased privacy and decreased battery use when disabled, presumably.