Why does proving lane activity in Kaspa scale with app usage, not total blocks?

In Kaspa's lane-local proof model, the size of a proof grows with how much an application used its lane — not with how many blocks the whole chain produced in that time. A "lane" is an application-specific slice of Kaspa's state; to prove something happened in a lane, a verifier needs a cryptographic witness covering only the changes in that lane between two global checkpoints. If a thousand blocks elapsed but your app only touched the lane ten times, the witness covers those ten interactions, not all thousand blocks. This matters because it keeps proof sizes efficient as the Kaspa chain grows: the cost of proving your application's activity tracks your app's real usage, not the entire network's throughput.