You do hodl your own keys with Ark, and those keys can exit unilaterally after one block (comparable to onchain levels of sovereignty, pluse state-chain security before that moment, which is less than a DryjaPoon channel but more than you can say onchain). In very high fee scenarios, unilateral exit is economically feasible for most amounts in Ark, but only for very high amounts in DryjaPoon channels. Running your node is a bit orthogonal. It's just that an Ark client node on top of a L1 node is a trivial thing, unlike a node to manage DryjaPoon channels. Protecting your own privacy is something you can do well with SOME current DryjaPoon channel setups (with unannounced channels, blinded paths and Tor, for example), and that is still slightly worse for Arkade afaik right now. But it can get very good (see the original Ark paper with also tumbling and chaumian stuff included). I agree with you that "90%, is very possible with LN". Today the LN is a universal, global, invoicing/hopping/swapping standard across many local security models with different security/usability tradeoffs: L1 (moon), ecash (minibits, fedi, mutiny, etc.), liquid (aqua, bull, breez, etc.), spark (WoS, Blitz, etc.), dryjapoon (phoenix, etc.). I think this complex variety will eventually collapse into a simpler number of primitives (namely: ecash for super small amounts, a mix of arks and spilman channels for average amounts, onchain for super big amounts). Using your own brain is very likely orthogonal. 😉