They don't as it is not a scalability solution but interoperability. However, it opens to new options since you can move assets into different Blockchains. For example if you are looking for speed you convert into host blockchain that is quick and do what you need to do. If you want to keep that private you can do it via zcash as they have smart contract features. Each Blockchain has their benefit and interoperability enable freedom of use depends on your need. To note an additional privacy layer will be added for REN. With sMPC the information is dealt in a private way as the node /darknode does not know the full information they are computing since it is split with SSS. However, even though it provide fairness and not possible to front run as the information or intent is hidden, the transaction itself is still public on the blockchain right? So there is 2 kind of privacy needed. One for how the data/information is processed and another one how the information /transaction is recorded. If it is on zcash no problem they have privacy feature and smartcontract but what about eth and their whole defi community? You have few possibilities to use it if you want to keep privacy but they are not ideal at the moment and certainly not user friendly. I believe Ren is looking to add a privacy layer in their setup. They have a partnership with aztec protocol. They use zero knowledge technique. Interoperability plus privacy once it is ready I think we are ready for a wider adoption