"Spark is statechains with extra steps. Federations are not worth much unless you’re a member, but then you’re faced with higher interactivity requirements than lightning. In the end, it’s back to custodial trust that can be bent against you."
I'm not technical but they said it needs trust only at the time of the transaction, and allows unilateral exit. I think if is true, is great no? And it's different than custodial, no?