On some pumps, the wires harden. And then they crack open at the point where the wire enter the pump body. Fine crack that will eventually trip the power at 3 in the morning. This normally happens after you did some tank maintenance and moved the pumps and the wires bend and moved.
Also heaters got a nasty tendency to work for years, then one night also at 3 in the morning to leak in water. Especially if the top of the heater is also under water.
On the pumps, if 24V, it will not kill you or wake you up properly when you dreamy eye feed the fish in the morning. You will feel it. 240V pumps, you will jump.
Best option is to have the tank earthed. Does not matter if 24V or 240V.
So in terms of your question, it does not really matter.
DC pumps do give you a controller and you can slow down the flow. DC tends also to be better when it comes to consuming power.
I use the feed mode on my DC return pump every time. That for me was the selling point to replace the Water Blaster with a DC.