Fun fact: Car dealerships are actually considered financial institutions under FinCEN regulations. Depending on the cost of the car/cash amount, they may need your SSN for reporting purposes.
> You are not required to have a social security number to open a checking or savings account.
Source: https://www.consumerfinance.gov/ask-cfpb/can-i-get-a-checkin...
Having spent more than a few years in FinTech, I know these things can vary from company to company as companies generally are required to design their own “risk-based” policies for AML and KYC.