For me it was more about flexibility. I like having both because not all power amps have both. Also, I'm thinking about getting some high-end active powered speakers. I can use my existing preamp to switch between my powered speakers and passive speakers between both sets of speakers without changing cables. Balanced cables are supposed to have a lower noise floor especially for longer runs but I think in reality it doesn't matter that much for the average audiophile.
Balanced vs RCA preamps
How important is it that your Pre-amp has both balanced and RCA capabilities? I’m shopping for another pre, most likely tube, and it seems to make sense with any future component that it offers both XLR and RCA. And to further complicate the search finding both these features plus remote limits the offerings for both tube and SS particularly tube.