I am taking about something like Celestia, basically the Blockchain (in this case Rootstock) doesn't verify anything, all transactions are pure data carrying, the only difference between OP_RETURN or Eth Blobs and what Celestia does, is that in Celestia you can add something equivalent to Nostr "kind"... This way people can query only transactions they are interested in. A simpler way to do this on Rootstock is just contracts and associated Events they emit. So let's say you want to make a Monero on Rootstock, you create a new contract, every time you make a transaction to that contract, it is only data carrying, thus miners don't validate anything except transaction fees. On the client side, you can see all these data, and you can run them as transactions against the smart contract state, deriving the new state, at the client side. But then when you want to take money outside of that contract to move it to another contract that says mimics ZCash instead, or if you have multiple Monero contracts each contain a shard, to keep things manageable on client side validation, then when you want to exit from one shard to the other, you need to provide a ZK proof to Rootstock that you did all the computation over that data carrying committed to that contract, and that the state after that computation contains a withdrawal request, not from one sidechain to another but from one contract to another... Does that make sense? This basically allows you to do 2/3 of what Drivechains does; 1. Freedom of innovation. 2. Sharding to limit the cost of validation As for #3; DA scaling, we keep it on Rootstock with Blobs and data availability sampling, not only because we can, but because the synchronicity between all these shards is super valuable for interop and atomic swaps, because you remove a major risk in cross chain transactions which is that some chains may reorg independently from others... But if you do DA on the same chain, then reorg is atomic, every shard is reorged at the same time. Also you don't have to keep bootstrapping merge mining (a new BMM has higher risk of reorgs, but in DAS, there is no reorg independently from Rootstock).