In general you’re supposed to use RCA for unbalanced main outputs like a mixer. And 1/4" Jack for balanced main outputs like an amplifier or active speaker.
However, I really don’t think it makes much of a difference
An unbalanced line uses one wire for the signal and another for the ground. Unlike balanced lines, unbalanced lines use the ground for signal return. In typical unbalanced cables, the ground is the cable shield.
one thing id suggest and it should go without saying really, is to have both and have more types of connections and a good selection of connection adapters, 1/4 jack - 3 pin XLR/5 pin XLR, RCA extensions, RCA - to 1/4 jack - 1/8 jack and male and female variations etc etc… you really do sometimes never know when you will need them
Keep both on hand…Most gigs will use RCA to either plug into a house mixer or a house party will accept RCA. I use balanced for my active speakers but thats also travelling around alot of computer wires so just to ensure a ground.