I think the reason you can't open other channels is because Phoenix connects to a trampoline node, which not many implementations support and even fewer actually run.
As for the backup seed, I've always thought that in case of a channel force close you can reedem your bitcoin with it on chain, no?
Hmm, trampolines might explain some of the speed difference as well, instead of my phone with a relatively bad connection having to figure out the route. But there are other trampoline nodes as well
As for the backup seed, I've always thought that in case of a channel force close you can reedem your bitcoin with it on chain, no?
Yes and no. The seed allows you to derive your bitcoin addresses, but you'd still be reliant on ACINQ in the case of data loss to be honest and give you your latest channel balance.
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You're right. Phoenix is pretty open about the trust issues in the FAQ:
Phoenix is trust-minimized, but not trustless. Wise people know that there is no such thing as trustless and that it's all a matter of trade-offs.
The following operations require trust:
channel opening (until the funding tx is confirmed) swaps (you pay upfront, and then our node does the swap) You can configure Phoenix to use your own Electrum server to watch the Blockchain and monitor your channels. This significantly reduces your dependency on third parties to secure your wallet.
For a more detailed overview of the trade-offs, see our blog post.
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