A lease is indeed effectively a financing option; that's pretty basic Finance 101. That said, one of the things one also learns in Finance 101 is that there are tax differences between how leases are handled and how capital expenditures are handled and that any calculation has to be made on an after-tax basis. (Which is a long-winded way of saying that how something like this should be treated from a tax/accounting perspective isn't at all obvious (to this non-accountant). Although I'm sure Tesla has vetted this pretty carefully.