If you are making a contract with a known bad payer or dishonest customer you take care to protect yourself against non-payment. I guess that insurance against non-payment for its Rafales by Indonesia was quite expensive after Indonesia had shown how little importance honouring its contracts was to it in its dealings with ROK.
Agreed, the KAAN specification (when defined) should suit Indonesia better than KF-21. Much riskier, though - there is no certainty when the engine will be ready. Perhaps that does not matter. With a lot of Rafales coming, a long wait for KAAN may be quite acceptable to Indonesia.