But for you, checks ARE accepted, as you are in california. Many (including myself) have paid with some combination of personal check, "bank check" (a pre approved check from a bank or credit union that is blank but drawn on the banks account, used to fund loans for things where the price is not known), cashiers check, or as you say EFT.
This could have changed in the past 10-11 months since I got my model 3 but in california at least, all those ways to pay were possible.
Its just states that dont allow direct car sales that have the issue of having to pre pay.