The pros and cons of low voltage lighting have been an issue since just after the light bulb was invented. The alternating current distribution system, and high voltage soon won the debate. Their capacity to transmit electricity great distances with less loss of energy along the way was a determining factor. The alternative system did and still does offer some clear advantages, though.
After inventing the light bulb Thomas Edison began using direct current systems to light individual houses. Later Nikola Tesla invented the transformer. This allowed alternating current electricity to be stepped up to high voltages and transmitted longer distances, and stepped back down to lower voltages to be safely used.
A bitter argument followed, with Edison arguing that his competitors were promoting a system dangerous to the public. To make his point he even helped to develop the electric chair to be used in public executions in public, to demonstrate the potential dangers.
Another known disadvantage is the thermal effect, whereby heat is generated in equipment at high voltage, causing fire risk. Another is surging, or over current which is a risk to electrical equipment. Also present is electrical disturbance whereby radiation can interfere with signal reception. It is also demonstrated statistically that electromagnetic fields are a risk to the health of persons in close proximity to the electrical line.
When considering a 12 V system we can see that there is no risk of injury or electrocution from the current. Meanwhile a 120 V or 220 V systems in use in the US. Their long history of deaths caused by electrocution from accidental contact with lines demonstrates that. Expense of operating can be 1/3 lower and LED bulbs have a much longer life as well.
A system using direct current could also be used in rural areas lacking distribution line access. It can also be used if the user wishes not to be dependent on the grid, which can fail to to deliver electricity at times, or if he does not want to pay monthly bills to the utility company. In situations like this electricity may be produced by solar panels, hydro power, wind turbines, geothermal, or fuel burning generators. Banks of batteries are used to store power for eventual use, as needed.
The light produced is of a different quality as well. Low volt bulbs produce a warmer appearing light. It can produce a more dramatic effect in architectural or outdoor landscape applications. It is sharper and clearer, making it suitable to direct specifically where wanted, or used as an accent. The quality is more natural looking and can also be used under water.
Meanwhile, high volt bulbs produce a more diffused light, which tends to scatter. It is harder to control and focus on specific areas. Much of it is lost into the atmosphere, causing light pollution of night skies and obscuring the stars from view.
The pros and cons of low voltage lighting should be weighed, balancing the desired effect, the cost, and safety. In considering all this it may become apparent that low volt lights have some distinct advantages, in your application.