This was at a car plant for people working in manufacturing.
Makes sense anywhere :)
Well, almost anywhere. There are places where if you have a beer with lunch and they saw you arrive in a car, they'll ask you for your car keys otherwise they'll call the police on you. Daily life works differently around the world :)
For those without religious objections or addictions, one glass of beer or wine with a meal is a complete nothingburger. Yes, it technically impairs your reaction times, but not enough to be a crime.
Though I suspect the BYD folks would want to avoid any hint of impropriety, so they probably will only let you drink there _after_ your test drive.
But I've only ever ate and drank at their showroom, I never went to the car side of the business.
In Singapore you wouldn't necessarily arrive in a car (yet alone your own car) when you go to a car showroom. I'm not even sure they'd have enough parking around there.
See https://earth.google.com/web/search/BYD+Zhongshan+Park+1826/... for the location.
And many people bring a companion when they do a test drive. Filling up the companion is perfectly legal and fine.
Just need to make sure that the driving customer has the beer after their test drive. You can fill up the companions before, however.
But to strengthen your point: I don't know for sure, but from what I can tell by looking at the place there's barely enough inventory at that showroom to allow some test drives. It's definitely not a car lot.