Pretty sure this just means moving around trailers on a parking lot / loading lot etc. Because you don't have to warm up the engine, and you aren't far from a plug, you could use these to just reposition the trailers. Also, you are working in close proximity with humans so being zero-emission is more pleasant environment and better for long-term health too.

It's a truck that never leaves the warehouse or "lot". They're just used to rearrange/move trailers.

a/k/a a "yard dog"

They are often built with a single-person cab with windows on all sides and in some of them the seat, pedals, and steering column can pivot around so you can drive backwards without looking over your shoulder.

https://typestrucks.com/wp-content/uploads/2019/08/13.jpg

Moves trailers around a lot. Useful at distribution centers, factories, etc.