On the one hand you could have intelligent systems running trains, highway traffic, airplanes (which they say is coming very soon), and so on. An airtight system could respond faster and make crittical decisions without emotions like fear, hesitation, etc.

Unfortunately many human beings would resist any change of that nature, but would likely in time become comfortable with the concept.

The bigger problem is that ultimately flawed people create flawed systems so whatever errors or catastrophes happen as a result of faulty AI would perhaps result in zero accountability.