If it's "bitcoin-like" then it will be similarly used as bitcoin. The efficiency blockchains offer is regulatory arbitrage. If the proposed system is not-actually-bitcoin-like, and doesn't circumvent regulations, it's hard to see what efficiency is being offered, over a centralized system.

I have no idea if bitcoin is useful for banks. What does seem fairly certain is that these "Bitcoin without the bad guys" pitches are pretty flimsy.