In many cases this was sufficient, but I can tell you from personal experience that many areas contain local anomalies which will not be detected or corrected until that area is resurveyed using DGPS technology. That will be a long time coming. Survey crews can only do so much each season. Given priorities dictated by economics, the hydrographic office will first resurvey areas used mostly by commercial shipping. Later they will survey the less frequented wates.
Planes work in three dimensions, but a boat is limited to two.
Planes approach the landing strip at high velocity and a few feet of error could mean a crash. A plane landing under IFR conditions has a decision point requiring split second timing to continue or abort the landing. While I do have a keen interest in all things technical, I always ask if I really need this or is it just a nifty techie toy to play with.