For example, I have a friend who's job is to have meetings with other people.

Most days, she drives to the office, then gets out of her personal car and gets in the company car, then drives the company car to the meeting, then to the next meeting, and the next one, then back home. She racks up a lot of car expenses, probably drives between 4 hours a day, five days a week. The car is leased by the company, all of the servicing is paid for by the company, all of the fuel goes on the company credit card. It's absolutely a business expense.

Her company doesn't allow it, but if they did she could totally park the car at home overnight instead of at the office. And then she probably wouldn't even need to own a car. Just don't drive it on the weekend or you could be done for tax evasion (that's probably why they make all employees park the company cars at the office - people would use them for personal trips).

Technically, owning vs leasing doesn't make much difference. But it is a hell of a lot easier (and therefore cheaper - because you need to pay someone to figure this stuff out) to pay a monthly bill vs a huge expense one year, then minimal expenses each month, then revenue when you sell the secondhand car.