[lbriner]

That isn't a great analogy because the expectation for electrical appliances in a boat/camper/cabin is much lower than it would be in most homes.

I had a battery fridge in a caravan (trailer) and it was very small and pretty rubbish, certainly not suitable for home. However, for a short stay, it could keep some basic foods cool enough to be safe.

As others have said, although it is fine on paper, as soon as you start talking about significant power, you are talking lots of amps, which means more risk of overheating and fire, potentially significantly larger (and therefore expensive) cabling and all of the switchgear that can support a few amps AC will not support the same current at DC so all your switchers are larger/electronic. There is also an issue of RFI which could be significant if you are switching high current DC loads.