I am also think so. Non-interactive one-side transactions which are prevalent in crypto space are convenient but inefficient. And this convenience is not free. Lightning Network is interactive, PayJoin is interactive. But the convenience of one-sided transactions make a gap for these applications and people don’t use them. Better UX for these applications and the underlying infrastructure can be developed by it’s much easier to start yet another blockchain project with regular wallet apps than to build a synchronous payment/financial overlay network. And and for it we pay with fees and lack of scallability.
I’d thought recently about something what can be called “Lightning DeFi”. Uniswap is the top gas consumption application on Ethereum. This is awesome how liquidity pools with automated market maker replace regular order-based exchanges. Buy Uniswap works entirely onchain, inefficient an unscalable. And such the app can be reworked into payment channel based. Why to use liquidity pools, when anyone can run software similar to Lightning Network node, but with several different assets, with a preferable AMM strategy to convert one asset to another, and earn on fees and slippage? End such system can be organically integrated in payment process itself. For example, Alice wants to tip Bob but has only Bitcoin and Bob wants to receive only USDT. Alice’s wallet just finds a path through a liquidity provider and pay in a single atomic transaction which is inter-asset as well as inter-chain. And with atomic multi-path payment Alice can aggregate liquidity from all the providers at the best price in simple “accept the payment invoice” workflow. And all the transaction fees, exchange fees and slippage fees will be combined in a single transaction fee which can be even hidden form the wallet interface as falls under fee threshold settings. A global scalable multi-asset payment network. But such network will require strong underlying synchronous messaging protocol, infrastructure and software.
MW/Grin is in an unique position here. For proper user experience Grin needs such communication protocol not only for applications like Lightning Network and PayJoins but for regular on-chain transactions too. And if a convenient way for non-interactive transactions were found Grin will be trapped by that convenience as any other blockchain.