Can you point me to some reading that explains ARK?

I see. The way I understood it, ASPs are lighting nodes too.

Actually ecash, Cashu/fedimint don't rely on a specific underlying funding technology. Lightning is nice because it gives instant settlement which is great for the swap ux. It could easily be interoperable with other shitcoins, L2s or even good ol' paper. It's just custodial tech