It becomes a potential problem if/when there is a significant redesign during the calendar year and two very different cars of the same model are identified by the same year. This hasn't happened with Tesla yet as there hasn't been a significant redesign of the Model S or X but I am looking more towards the future.How hard is it for insurance companies, banks, and shoppers to just use the car year? Is that really so different from a formal "model year"? Every insurance company knows perfectly well what year the car was made from the VIN. Shoppers can check the month and year of manufacture from the door plaque. I don't get the "confusion" involved.
Insurance companies use pricing sources like KBB, NADA and others to come up with claim amounts for things like ‘totaled’ or stolen cars. Banks/lenders use price guides to determine a car’s value and how much of a loan should be acceptable towards the car. If the guides can't/don't distinguish an 'all-new' car from an 'old version car' because they both have the same year (e.g. both are 2019s), valuations can become a problem for everyone involved.