You know how to use it? Tell me, I really tried to use him in 1vs1 and 2vs2 and I didn´t have much success.
Smoke is great if you face multiple maxims or Vickers, but when you would be better off with a mortar
-> better to safe muni and use smoke barrage from mortar. The accuracy buff is not that useful either, grens have usually more than enough accuracy, its survivability they lack -> better to invest in lmgs for more damage. And finally the vet 1 ability is overpriced and situationally. 80 muni for a panzerwerfer barrage midcooldown? Not that great either, also you need to have t4 for that.
So that´s my conclusion after several games. But if you have another way of utilising him I want to hear it, because I generally like the concept of the artillery field officer.
If you are going to use the Arty officer, you will have to go for the "joint operation doc" to really utilities it. You are using it with the one that has the tiger in from what i can gather(since you only mentioned the panzerwerfer), that of curse is pretty useless, since the only thing it will really benefit as you stated is the panzerwerfer. Arty officer is not a direct fighting unit, but a support unit. The arty officer is great for buffing infantry, and it is super cheap too 25 muni. And the only ability that is locked on the unit behind vet is the medic kit for 20 muni. Everything else is there from the minute you spawn it.
They way you have to utilities it, is to have it in the back. Behind your mainline infantry and building a Lehf to really get any effect. I've used it in 1v1 to great success before, since i can have one barrage in the fight area where my troops are, because i make my arty officer follow my main assault so it can also buff them, then i can use the barrage on the howizter itself to barrage the enemy main base. And if you use the barrage on the arty officer as the howitzer is on the last salvo, and you set the barrage in the same line as the howitzer then it will start shooting directly no breaks in between, and it is really effective because your opponent wont expect that.