Certainly the suction dredge addresses the primary issue of caulerpa in that it smoothers everything. Obviously these are trials at the moment, but you would expect that if you physically remove the smothering caulerpa the rest of the benthic environment will bounce back. It may be like kaykuya (spelling, the grass that grows well in coastal environments). Near impossible to permanently eradicate, but perfectly manageable if you give it a regular mow and weed-eat it once a month.
There is nothing technically complex or particularly expensive about the dredge. A long reach digger, probably