I don't see why not, it's not like you can buy a car anonymously. If anything there's more security there than with the coffee, and no one is going to attack the Monero network to create a double spend for the price of a car.
In practice people (e.g. exchanges, that know who you are after KYC) still opt to wait a little because if something does go wrong it's a hassle to actually get paid. For the same reason, we are likely to check some of the bills in a large cash payment for authenticity, even though we have effective recourse through the police and the judicial system.
You can buy a car with cash. Monero is digital cash.