Let's talk about each of your requirements one at a time and then draw a conclusion, shall we? (Note: all the following are assuming clear weather. Airships are not only a liability in foul weather but can actually endanger anyone nearby if they are driven into the ground.)
With a top speed of just under 60 mph the NS-class was not exactly a hot rod. It was faster than a number of other vehicles of the same era, but not all, and relativity isn't everything. Airships are also somewhat lumbering and hulkish, so the deployment of troops onto the ground will leave the airship exposed. Lastly, airships are loud and easy to spot, so any element of surprise will be completely lost.
The one thing the airship has going for it in this application is that few other vehicles will be suitable toward rapid response. Those that could move fast enough were more limited in scope (trains have to follow rails and airplanes have to land in semi-specific places). As a result, the airship is potentially useful simply because nothing else can do this, even if the airship isn't exactly perfect for the job either.
Search and Destroy
While historically fixed-wing aircraft were employed most often as bombers, airships are not completely unknown to the concept. Airships could typically carry far more weight than an airplane, allowing for a bigger payload, but again the airship is lumbering and a veeery tempting target. It might be able to put the hurt on some poor sap on the ground, but it's a bit of a glass cannon; one good shot into the substantial gas bags will cause a leak and potentially ignite the hydrogen. Oh the humanity.
As a high-altitude spotting platform, however, things might be somewhat different. Artillery was the strategic weapon of choice during that era, and anything that could make it easier to deliver ordinance on target was useful. Consider this: an airship searches out its target but does not engage, instead signaling to a nearby relay post the exact position of the enemy. Artillery opens fire, and the airship can report success or failure, and how the artillery needs to adjust its fire. This could be a truly deadly tag team, though it still does leave the airship exposed (if it can see the enemy, the enemy can see it).
Depending on the situation, airships could be ideal for this application. In a hot-zone, the airship would be vulnerable, again because of how tempting a target it makes, but in a safer area the airship is better suited than an airplane since it can take off vertically and land almost anywhere there is flat-ish ground. It can also carry more passengers/cargo than a contemporary airplane so it opens up some interesting options. I can imagine an airship as a small mobile field hospital, capable of deploying faster than anything else of the era, or performing emergency airlifts to safety, whichever is needed.
Show of Force
Now here is where the airship shines, assuming your enemy does not learn of its obvious weaknesses (which is a big if). Airships are big, loud, and intimidating. They represent basically the pinnacle of engineering during your era, and unless the opponent gets wise, they should be suitably cowed. But we all know that already; they're just so damn cool.
So yeah, overall I can at least plausibly imagine an airship performing some of the above tasks. In bad weather or under enemy fire it would be tough-to-impossible to do anything, but in ideal circumstances things would be just fine. For your game that might actually be nice, since you never want something to be overpowered. Maybe the airship can perform a bunch of support/utility tasks, and can be countered by clever tactics and play.
Anyway, I hope I helped. Good luck!