I like the idea of lightning as the language all the other bitcoin things speak to each other.
In Riga, the Fedimint user initiated the payment request to their counterparty by swapping locally minted Ecash with the Fedimint Gateway. On the Arkade side, the user received a VTXO that was swapped to them via Boltz who generated the invoice, and received the payment, on the Lightning side. This payment was executed just like our example outlined above.
The swap service does seem to be the single point of failure here. I know there are many different swap services, but it seems like a lot of these different layers are relying on Bolts. Given the current legal climate, I wonder how long that will last.
None the less, this does feel a little bit like the dream of exchanges having private lightning channels with each other and settling back and forth while rarely hitting the chain.