They propose a decentralized system to store intermediate states, instead of relying on a blockchain-like structure. The author believes that existing sidechains are centralized, with the exception of Lightning Network. They also criticize the idea of having a blockchain on top of another, and claim that this can lead to a very centralized system. The author suggests using a distributed escrow to store intermediate states, which would not necessarily have to be blockchain-like. They acknowledge that this may be easier said than done, but believe that sidechains claiming to be decentralized are misleading people. Lastly, the author points out that the proposal does not address what happens if the platforms supporting the smart contracts go down. The linked article proposes an alternative method for implementing smart contracts without launching a separate blockchain or sidechain. This method achieves security similar to federated sidechains, while offering additional benefits to privacy and smart-contract-patching. The author's concerns about centralization and the use of sidechains are not directly addressed in the article.