Setting up Inverter and external charger w/ new batteries

Higher voltage greatly reduces wiring and switching losses, less current to deliver same wattage.

Also makes pack construction simpler, you don't need super heavy parallel cross-bars.

Replacing failed cells in the "deep desert" is going to be difficult either way. Also no reason you can't wire 4 or 10 12v packs in series if you're set on buying off the shelf.