This also applies to the drug being used for workers compensation cases, employer insurance, and government-run insurance (Medicare). It also makes sense from a business standpoint. The more insurers that cover the drug, the bigger the market to sell it to. If the drug in the US starts at $2000/injection and isn't covered by insurance, less are going to buy it. Covered under a typical drug plan might get it to 50% - 10% of that price.
Also, actuaries in the health insurance industry know the comprehensive cost of hearing loss over the life of an insured person.
If FX-322 is a cost effective route, and thereby modifies the lifetime cost of hearing loss to the insurer, by increasing quality of life measures, it may be considered a preferred/preventative treatment.