DC has a higher danger of arc faults than AC, and 48V is enough to sustain a short arc. But 48Vdc has less danger of either shock or arc faults than 120Vdc, and DC has a lower risk of shock than AC, because it still
usually can't drive enough current through your skin to kill you. But you are correct that people can and do die from 48Vdc shocks, for example when their welding gloves are soaked with sweat or they're immersed in water.
You need thicker wires with 48V than with 120V or especially 240V, and the higher currents required at 48V can create more risk of fire from overheating conductors, for example in a wire that's too thin or a spring contact in an outlet that's worn out.
Perhaps you are implicitly comparing 48Vdc to 24Vdc, 12Vdc, or 6Vdc, rather than the 240Vac or 120Vac I was comparing it to. Those lower voltages do indeed need even thicker wires and pose even less risk of shock or arc faults than 48Vdc. I think 24V is the minimum to maintain an arc in air at atmospheric pressure, and it's really hard to get one started using a 24V supply; you need a high-frequency start circuit or a substantial amount of inductance in series.
48V is the maximum usually considered safe enough to not require compliance with any kind of electrical code; an expert electrician from North America once told me that it's in a category known to electricians as "bullshit wiring".