An insurance requires an independent assessment that a certain event has taken place (e.g. a car accident) and of the circumstances surrounding the event. A loan requires the ability from the lender to initiate legal action against the borrower in the event of default. Smart contract can't help with that or make any of that more efficient.
To play the Devil's advocate, if the independent assessment can be provided by a neutral third-party API, then you could have a smart contract pay out depending on the response from the API.
Realistically, this requires more Data-as-a-Service startups, so there's a bit of chicken-or-the-egg difficulty here.
