Why Do Shopping Carts in Supermarkets Turn Into Four-wheel Steering?

I haven't seen a shopping cart with front wheel steering, but I think four wheel steering has the following advantages over front wheel steering:

1. It can move 360 degrees without dead ends.

2. The turning radius is small, and it can be turned in place (when there are many people, the shopping cart with front wheel steering turns in the supermarket is a nightmare).

3. The shopping cart with four-wheel steering may be more favorable for the four wheels to be embedded in the groove of the escalator when going up and down the slope-type escalator in the supermarket.

4. When the supermarket staff stack the shopping carts into several long lines for storage, the omnidirectional motion is much more convenient than the front wheel steering shopping cart that must be moved forward or backward.