It is not a scam. And there is no catch. They offer to handle the insurance so the family doesn't have to fork over the funeral expenses before the insurance check clears which can be after the funeral has occured.
Its either have them handle it or pony up the funeral expenses on or before service. And YES they will ask for payment during the service if funds have not been paid and they aren't handling the insurance claim. Unless the estate of the person who died has money(in most states the funeral home is usually the creditor with 1st priority in probate) they will want their money by day of service or the right to process the insurance claim.
If someone can cut a check for the funeral expenses without a life insurance policy payout, they should do it. If they cannot, there is no reason not to allow them to process it just make sure to read the paperwork before signing anything. The funeral home just wants to get paid. There are a lot who try to skip out on paying which can make things awkward at the service.
And $15k isn't a red flag as some might believe. Any upgrade over a basic casket+burial service can quickly hit $15k.
Also, FYI, if you aren't planning on paying for a funeral out of your own pocket DO NOT BE THE ONE who makes the arrangements.