ZKs offer a bunch of promise across many applications. Bullish on those. They're clunky on the platforms using them and have quite a ways to go to prove themselves, from settlement to interoperability, especially interoperability which is the LNs specialty.
But why would SN need to be a smart contract? The beauty is that it's a simple HTML site anyone can access on the web from any device anywhere, sign up instantly, and it has a free disposable wallet attached to your username that's interoperable with the rest of the entire Lightning Network. You don't have to do anything or even keep a balance. I'd say at most you just want the wallet to be non-custodial, that's it. I think the LN will offer plenty of solutions for that in the near future based on the work of today.
Because if it were you wouldn't have to trust any of your sats with it. You'd literally just be transferring sats from yourself to whoever you're trying to upvote and to the contract itself at the point of transaction, otherwise your sats stay in your custody at all times.
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