Composer has many useful functions to help your authoring processes faster and more enjoyable.
This will visualize the direction of the possible part movements. Please note that the green arrows are directing outward for each tire.
When you drag one of the green arrows, you can see that each part is moving to the direction indicated by the arrows. When the Local Transform is enabled, all selected parts move along their own directions going outward from the assembled car, instead of all of them going toward the same direction.
The benefit of this function is that with one single operation, you can assign the same movements to all the referenced parts. There are many cases in illustration creation or assembly instruction creation where you need to disassemble multiple parts, and this function should save time and avoid errors by moving instances to their appropriate positions with the same amount.