Well, I was more or less saying the Tesla Cannon for the luls. If used at all would be vastly overpowered and silly as hell. More of an ongoing meme then anything that should be used since it doesn't really go with the rest of the weaponry. But it gets one thinking, and that's good for brainstorming.
My main thought that goes against it is, this is steampunky. There is no room in the world of steam for electricity. And once you introduce electricity the entire world changes. Maybe I am just being a bit stubborn on the idea of changing the world of guns, but I do not see a need for tesla anything.
However, the use of electricity powered items predates airships beyond hot air balloons. The first arc light was made in the early 1800's, and was used for movie projectors up to WW2. The first steam propelled airship was 1852. Not to mention other picky inconsistencies without any electricity (in example, how to captains talk to each other without a radio?)
Truth be told, this game feels more diesel punk then steam punk, and has elements of both in it. It's kinda of its own thing. While it does have the steam punk aesthetic, I see the use of oil and engines rather then actual steam. And the guns range wildly between eras (the heavy flak looks like a ww1 artillery piece). Actual steam punk would have more flintlocks, gears, and well, steam. But we see oil, kerosene engines, ww1 inspired clothing (the Lost Soldier outfit in particular) and this, if we want to be picky, is leaning towards diesel punk. In which early forms of electricity would be very plausible.
There is a lot of inspiration that could be drawn from weaponry created in the world wars (and thus when electricity was very present), and later altered to fit the aesthetic better. After all, we use a fair bit of imagination for the setting as we know it.