The kinds of structures you can make are shown in figure 1 above. If you are making a permanent bridge, then you can pour concrete over the structure. Figure 3 Temporary bridges are needed wherever floods are prevalent. The vehicles you see in figure 2 are not going anywhere when the flood water rises to around 3 feet. Since it is difficult to make anything like this in the time scales allowed with conventional approaches, there is immediate demand for machines that can be procured by local authorities and emergency services to alleviate their immediate problems.
Bridges are the first casualties in earthquakes, flooding, wars, mud slides and severe storms.
A machine that can automatically build bridges will always be in demand. Since they can cost a million dollars or more to produce, you don't need to win a large numbers of contracts to be in profit. Most cities that have been built up along side rivers always require new bridges but cities can't afford expensive new bridges so anything that makes them significantly cheaper and dual use will fetch new orders. Many parts of the world like the southern parts of the United States are at or below sea level and prone to flooding and a lot of the land is marsh land. In places such as these, highways become bridges several miles long in some places.