How is a credential on KILT paid for?
Reading a blockchain is free – blockchain only costs for writing.
KILT is a permissionless blockchain. And permissionless blockchains need ways to reward all the people who actually run the blockchain. So some kind of a monetary system needs to be built in. For KILT, this is KILT coins.
So the person or organization building the application just puts a piece of open-source software up on the KILT blockchain. They need KILT coins to write on it and nothing to read from it.
And because KILT is in the Polkadot ecosystem, it’s possible to predict the cost of a transaction, so that it can be built into a business plan.