But other than saving you the trouble of pushing them, electronic shopping carts are not as good as physical ones. You can't see the goods in your online cart. You can't tell if the cart contains all the ingredients you need for a recipe. Each employed some variety of shopping cart. Sadly, all the carts shared similar weaknesses.
Visibility is the first problem.
Sites should not hide their shopping carts on separate pages. This design makes shoppers either delay all analysis and reconciliation to the end of their visit or flip back and forth between item pages and the shopping cart. The cart should always be visible, in a window whose size you could control. To give credit where credit is due, NetGrocer, the one exception in our visits, has taken some steps in this direction. It displays a single-item, scrollable cart on the bottom of the screen, and that cart shows the total cost.