When using a lift option on a container such wagon, garden shed or knarr, it picks up first lift able object from such container, without opening it's interface.
It's cool when You can load 20 logs / corpses / containers pretty fast but unload is tedious and pain with opening it each time, clicking object You desire, then clicking a way or something to exit it. Or something like with boats / carts, where You click on place and take object out but that would need a special place as I don't see getting from wagon especially each piece like from boat.
Short: QoL, You can't lift knarr, wagon or shed, so using this would be a quick way to get object from it, without having to interact with flower menu and opening it.