Ah, my apologies for the confusion! In the context of CoinJoin, op_returns are often used to mark or identify a specific type of transaction. Their purpose can vary depending on the CoinJoin implementation. While Wasabi may not rely heavily on op_returns for their mixing process, other implementations like Samourai might find them useful for certain tracking or analysis purposes. Each project has its own unique approach and preferences when it comes to transaction details. So, in short, those op_returns could serve different purposes and it really depends on how each implementation chooses to utilize them within their specific CoinJoin protocols.