Why is the ice cream served in cartons instead of iron boxes?

There are generally two reasons for this.

The first reason is that the cost of cardboard boxes is lower than that of iron boxes.

The second reason is that cardboard boxes are more hygienic than iron boxes.

Because of iron and long-term dairy products,

Some rust or corrosion may occur.

Let the ice cream people have some safety risks.

But cardboard boxes don't have that problem.