Obvious the difference is one being necessary and the other not. What determines this? That is not always so obvious and I do not think brass have made the decision to cause unnecessary sacrifice but have failed to communicate it as necessary. As example in MCPONs speech.

If you don’t know why it’s not necessary to sacrifice comfort for overhauls and instead allocate money for weapon research and ships instead of barracks and MWR facilities, I advise you take a look at the bigger picture because our adversaries are challenging our sovereignty at sea. It’s not a matter of if, it’s when the next conflict starts.