Professional engineers are governed by the Engineering Practice Act
You might think this does not affect you but it does. For years the Texas Engineering Practice Act exempted single-family houses. In other words, if someone practiced engineering by designing a beam to carry a load in a single-family house, that act was exempt from the requirements of the Texas Engineering Practice Act.
Engineers bring credibility
Engineers are independent
Engineers can bring a sense of reality
Structural safety issues
Structural integrity issues