There are several factors here. Firstly, there's opportunity cost, i.e. what you would get with the money elsewhere. If you have higher interest opportunities (investing, paying down debt) elsewhere, you could be paying that down instead. There's also domino effects: by reducing your liquid savings to or below the minimum, you can't move any of it into tax advantaged retirement accounts earning higher interest.
Then there's the insurance costs. You are required to buy extra insurance to protect your lender. You should factor in the extra insurance you would buy vs the insurance required. Given that you can buy the car yourself, catastrophic insurance may not be necessary, or you may prefer a higher deductible than your lender will allow. If you're not sufficiently capitalized, you may need gap insurance to cover when your car depreciates faster than your loan is paid down. A 30 percent payment should be enough to not need it though.
Finally, there's some value in having options. If you have the loan and the cash, you can likely pay it off without penalty. But it will be harder to get the loan if you don't finance it. Maybe you can take out a loan against the car later, but I haven't looked into the fees that might incur.
If it's any help, I'm in the last stretch of a 3 year car loan. At the time paying in cash wasn't an option, and having done it I recognize that it's more complicated than it seems.