This depends too much. It’s standard at many stores to have someone who goes out and fetches all the carts. They have to do this anyway because of the cart corrals. This sounds like some idea by a European in some tiny parking lot without those.

People here have mentioned it only taking 30-60 seconds, which definitely speaks to European centric stuff. A lot of the places I’ve shopped where I’m using a cart, it takes minutes to return. That’s why people aren’t doing it. You spend 1-2 minutes walking to your car. That’s why they leave the cart, it’s an extra 5 minutes round trip. But for an employee who is going to be going around the lot anyway to do this job, it’s no extra added time.

This also ignores that people like me will sometimes pickup a cart like this on the way to store if it’s convenient. We also don’t leave them in parking spaces or whatever. We leave them somewhere reasonable.