If a standard AC switch is rated for 15 amps, or 1,800 watts, there’s a reasonable margin there for derating, given that a DC 60 watt equivalent bulb will draw about 8 watts. I would be concerned about the longevity of a.c. contacts, but the switches are cheap. As are DC.switches too. If they are U.L. rated is a good point, which I guess depends on how off grid a person is.
Yes, fuses should be used on DC, contrary to conventional wisdom fuses are much superior to circuit breakers.
8 watts at 12v is 2/3 of one amp, the currents needed for practical lighting are minimal.
I believe you had previously mentioned that dc systems below 150W? are outside of code requirements anyways?
I personally am not too concerned about circuits far below typical automotive ones.
My main point here is efficiency. A straight dc system avoids inverter losses, and rectification losses, the power will be used roughly 40% more efficiently. That means lights on longer, or smaller solar array, or smaller batteries. To me that scale of energy and materials savings is a big plus.