You can only explode a vehical once by the way....
But besides that... Isn't it funny! I love doing that to my boys, or to driving recklessly with bikes and trukks and smacking them into terrain. For tactical advantage and simply because its characterful I let absolutely nothing stop my ork horde!
But in addtion to poping vechials, its much more fun when you surround the access ports before you pop em. Even just a trukk or buggie in near base contact will do it.