Voltage vs Current for DC electronics?
Relays come in different voltages and typically, for any given family, the power rating and switching performance is basically the same regardless of the voltage. As such, which one you chose will come down to other factors.

Rail availability. This is often the prime mover when you are only using one or a small number of relays. In this case it is prudent to find a relay that uses a power rail that your system already has rather than adding the cost of a new power supply.

Current Distribution. If you have a significant number of relays then distributing the currents involved becomes an issue. If you use low voltage relays, not only do you need a beefy expensive power supply, but you also need to have heavy wiring or even solid bus-bars to effectively carry the required current to the farthest relay, under all conditions, without incurring so much voltage loss that the relay no longer performs reliably.