Yeah I have been rolling around use cases in my mind for the past few weeks.

Track and Trace:

Peer A and Peer B are known to each other and will have several contracts that are exclusively used between the two parties. Their main reason for using the blockchain is to provide a trustless audit trail on their interactions.

Peer A (shipper) will use their side channels to store contract rates for their different delivery routes and weights etc (data that would give a material advantage to competitors if published publicly) with Peer B, C, D, E (each having a private channel)

Track and trace of a shipment can be recorded on the mainchain ETC on a contract using iot sensors(or whatever)

and final settlement can be done using the rates agreed upon by the two parties on the private channel.