The idea is that payment channels only work with liquidity, and nodes locking up funds provide essential routing service to other nodes should be compensated for. The paper calculates specifically how much the interest rate should be depending on the network graph using an opportunity cost framework. Intuitively, nodes sitting in heavily trafficked area of the network should be paid more than those situated otherwise.
is this working with a dex to provide the liquidity and shadow pricing being paid back out over time?