Hiya Pia, here in lays the difference. Living in a boatyard or marina is totally different than cc,ing as you will know. Having services on hand, elsan or pump out, water, power is easy. Now, let's take a day like today here in Suffolk, it's blowing a gale water tank is getting close to empty, cassettes need emptying, or tank pumped out, no vehicle so the boats got to move whether you like it or not, then you get to the elsan and find it blocked/out of service, the only water point for miles is frozen. I've said from the outset that I'm not trying to put Gromett off I'm just saying it as I saw it many times.
Those are all issues I have living in a van. I use CL's during the winter which tend to be miles from the nearest shops/supplies.
I have had frozen grey tanks, fresh water taps that can't be used for a week or more at a time, blocked in by the weather and no way to get calor (early days) or my LPG tanks topped up. Power cuts that lasted 8 days and many more issues.
I am accustomed to the harsh life of living off grid in the middle of nowhere. I have work arounds for all problems you mention.. I am not your average house dwelling joe blogs with no idea about life off grid .