As you know the Litecoin implementation of MimbleWimble on extensions blocks is already running on testnet. They will go mainnet in a year. I think this could be a great improvement for Bitcoin. We could use Bitcoin for private transactions when required, no need of coin mixers or Monero anymore. Exchanges like Coinbase will not delist Bitcoin as they already have ZCash which have public and private transactions too.
In the rare case there is a hidden inflation bug, new coins created in the extension block can't infiltrate the canonical chain because the amounts are public, so the bug would be detected sooner or later when someone can't send back his coins to the canonical chain.
The developer has said he's going to write a BIP and make a pull request to Bitcoin. What are the chances it's approved?