Are you saying to lubricate the threads and periodically remove the insert to prevent it getting stuck?
You see many of them in Thailand unable to remove them. Thats what happens when you keep the tanks on a boat, never wash them, and never service them for 10 years. If serviced regularly they are no issue. Thats not to say you must service the valve yearly, but how about taking out the insert periodically and washing it as its the bit of the valve exposed to salt water through the thread.
For those who espouse using yoke only over these valves, if you dont service the thread on your yoke reg, it gets tight too. Same same. Regardless of the type of gear you use, washing it and servicing it regularly should give you years of trouble free use. I have had DIN valve tanks for some 11 years and have never had an issue with an insert.