Who says it isn't custodial?
Discussion
spark markets themselves as a non custodial solution for things, i dunno
A mechanism for zapping on Twitter is separate from the Spark protocol though? Maybe I missed some claim
I don’t know anything about spark so if you say so
I'm unsure of Spark myself, but it sounds like "BitBit" is implementing zaps, which obviously can be done a number of ways. Might just send an app notification and use background processing to complete the zap
Part of this video explains how the idea of wallets as rewards could work. Sorry in advance for the Taproot Wizards watermark, that wasn’t my idea.
"As long as operators delete keys"
Honestly, I'm not sure how anyone makes it past this sentence. If I'm going to trust them to delete keys, why not just go custodial?
A tree of "unilateral exits"
They have a lot of complicated key rewriting making it difficult to understand, but any scheme of this nature needs to prove it isn't vulnerable to an early transaction forcing a whole subtree on-chain to defend funds. Your 15,000₿ wallet isn't worth anything if someone waits for a high fee environment and it takes 10,000₿ to defend, plus another UTXO to get back in.
But I've been hacking on something that I think is better, so there's some conflict of interest here