I think the issue is half of a regular truck or a 'Murica' truck. I got loaned one of the latter last I had some work done on my regular vehicle, it wouldn't fit in the garage and I had to actually use the steps/handles to get in. As a 6 foot plus person that's kinda abnormal.

You know what is roughly half the size of an American pickup truck and very common? A sedan. Like a regular sized car.

The annoying thing isn't using a common object to show scale. It's that they are cutting it in half. Like, you have other whole objects to choose from. It kind of ruins the point.

That's what frustrates me about the title at least.

The problem is he’s Unfortunately, short, so he has a hard time on visualizing things like the size of pick up, which are quite large

It's funny because every single person who uses the metric system can visualise what 1-4m³ looks like, which many of these "random object" measurements often fit into. So much easier as there's no definition of what size a "pickup truck" is.