The ability by the contractor to put several risks under one cover is important.
The contractor has several risks at hand that may destroy his repute and lead even to bankruptcy.
You may never imagine a road construction firm having barely finished the work and a flood or land slide washes away the same. It is equally not far fetched for a building under construction to be destroyed by a fire, storm and similar calamities.
The public may be affected by your work and you have to compensate them. Hence the constant reminder that beware of falling debris, bodily injuries and even death either to the public or your own employees are not rare occurrences. Property may equally be damaged.