When you're paying for things, and can pay for several things at the same time, it makes sense. I helped my mother pay her property taxes this year, and for two

When you're paying for things, and can pay for several things at the same time, it makes sense. I helped my mother pay her property taxes this year, and for two properties we had to make four payments. Without the shopping cart (or a functional equivalent) I would have had to enter my payment information four times instead of once.