Sure, but it's another thing that they have to deploy and position around until you drop it. The more problems you can add for your opponent, the better. Another Gunhauler doesn't add anything more for them to consider.
It's not THAT short. You land 9" away and drop the first part 4" into their army. The other two corners go 7" more, meaning he needs to screen a full 12" to be safe from the immediate effect, then he still has go all the way around it. You don't have to use it right away either, so even just holding it on the first turn can be good since now he has to worry about screening all the way through till turn 2. Now you can drop it on the objective he's decided to prioritize.
How can it be easily countered? It literally can not be stopped when you use it, screening it is a pain, and it needs a 9+ to unbind. That's not EASY except for a couple very specific lists.
Yes it affects you too, but as long as you choose where to use it well, it should literally never be an issue for you. Drop it where they are deployed, or on an objective you don't care about until the later part of the game. If it forces him off an objective, you can drop a Gunhauler on it and happily take his objective at the cost of a few mortals (that you will easily repair).