Although technology is a large part of the commercial marine work industry, there's no substitute yet for human divers, especially in situations that require finesse. We simply aren't at a point where machines can do all of the necessary work for an underwater job, so employers need to insure both live crew and the remote equipment they manage.
From energy operations to dam inspection to salvage, using ROV's has certainly become an accepted practice. However, human diver oversight can improve operational effectiveness, and may be the norm for the coming years. John Roat mentions this point in an article for the Divers Association.
"The main customer of commercial diving services, offshore oil and gas producers, were led to believe that a working diver would be replaced by technology in the near future!" he writes. "That is not the case now and will not be for the foreseeable future." Roat also references the lack of personnel present to respond to major issues at underwater sites, especially in an environment as full of energy activity as the Gulf of Mexico.
While a diver can be agile and intelligent, ROV's provide the benefit of prolonged exposure to extreme depths, saving the time it takes for a human to prepare and decompress. On the other hand, the expense of ROV's make them a costly loss should they be destroyed during work, and using them also requires proper training.
Companies that specialize in commercial diving and marine services will need to find the insurance that covers each aspect of their business and aids in timely performance. Using multiple types of equipment around human divers can put them in greater danger.