German Health Insurance allows for 3 routine ultrasounds during pregnancy, which is a nice benefit because in many countries it can be less than that or none at all.
Determining the sex of the baby is not part of the normal routine.
Additional ultrasounds can help determine the proper growth of the baby and visualize that the amount of amniotic fluid is correct. Some parents simply enjoy seeing and bonding early with their baby.
Additional ultrasounds help detect problems early so that if necessary proper intervention can be obtained.