Sorry for replying to an old thread, but I wanted to respond to this.

I totally understand why blockchain isn't the standard for everything right now; my statement was in regards to formal methods to ensure correctness. For example, "reversing" a transaction could totally be modeled in TLA+ (and probably other systems, I'm just most familiar with TLA+ than most other systems), which would provide model checking (and possibly even proofs) that you would not otherwise have.