As with all decisions, there are tradeoffs. For a little more up-front complexity and a tiny nominal performance hit, this allows maintenance, encryption, non-uniform storage paradigms to suit individual ledgers, rolling upgrades, storage location migration, and other cool stuff which is typically painful with traditional all-or-nothing RDBMS architectures.
A flip-side view is that, in many cases, if you really want to trust your data (not your database), then you want to be doing this stuff to a large extent anyway... which means that, basically, it's just enforcing good practices that should have already been present.
Complexity and per-TX latency increases, but for that you get maintainability and a great deal of flexibility. Nothing is free... take your pick!