Why don't they just issue some debt to retail somehow instead secured against the freeholds?
Usually something like this will be structured so that the landlord shares in the earnings of the tenant a la Westfield. If the deal is very favourable to the landlord, it will detract from the value of the Casino business and vice versa. There are very few suitable metrics for setting the commercial lease on such a specialised portfolio that would not involve the landlord's earnings being based on the performance of the tenants. So the income is really going to be a derivative of the tenant's businesses to a large extent, probably with the non Crown businesses being managed by the REIT on varied types of leases. However even what the non Crown tenants will pay will be loosely based on the performance of the casino based on visitor numbers, and spending habits etc. It doesn't seem to have all of the hallmarks of typical REIT to me. If it isn't heavily geared up, the main benefit of the REIT would be that it has real estate as security.
Short term investors may make an error and pay more or less than what it is worth - long term there is still no magic pudding.