The usefulness of adobe is that it is made from mud. So long as you can find a supply of mud - such as from a river bank – you can make mud bricks. So it does not even have to cost you anything. That is why many poor people made their houses from mud. In poorer parts of the world, many still do.

You can either make adobe into bricks, and use them to build thick walls, or you can paste it all over a frame of twigs.

Because adobe is mud brick, it is not useful in parts of the world where it rains a lot unless you protect it. That is why many houses that use adobe have roofs that go out a long way from the walls. That is, they have wide eaves.If they don't, the chances are, the wall will have to be repaired every year.

The difference between adobe and proper brick, is that adobe is sun-dried, whereas a brick is kiln fired at a very high temperature. That is, it is baked in an oven.When clay is baked at high temperatures, the clay changes and begins to fuse together. It will not soften again if the brick gets wet. It is also far stronger than adobe, which means walls can be higher and do not have to be so thick.