When are Bombers better than Sprayers?

In Creeper World, there's a marvelous substance called Anti-Creeper that is exactly the same as the Creeper that's trying to kill you, with two key differences that make it great for holding territory:

1. It doesn't try to kill you
2. It mutually annihilates any Creeper it touches

There are two delivery methods for this miracle material: Bombers and Sprayers. Sprayers are (occasionally mobile) ground-based turrets that shoot a steady stream of Anti-Creeper, while Bombers are, well, bombers: they pick up Anti-Creeper at a landing pad, then drop it wherever you want it. There's another flying unit, the Strafer, that simply shoots Creeper and destroys it.

The problem I have with Bombers is that I can't think of any purpose for them that isn't better served by Sprayers or Strafers. If you're trying to set up a base somewhere inside a pile of creeper, then the Strafers are (in my experience so far) faster and better at destroying Creeper, while landing a Sprayer (possibly backed by a Guppy or two carrying Anti-Creeper reloads) gives a much more steady supply of Anti-Creeper than the slow-moving bombers, once you've Strafed the Creeper down to reasonable levels. (For reference on my skill level, I've completed the main campaign and a few dozen additional levels, of which about a half-dozen were in the hard-mode Tortured Space worlds.)

I have occasionally built squads of bombers to drop unholy amounts of Anti-Creeper somewhere, and they can create a wonderfully large puddle of Anti-Creeper, but by the time I can manage to do that, I am filthy stinking rich and am simply cleaning up the last of the Creeper. At that point, I can build lots of anything, and swiftly overwhelm whatever Creeper is left.

In what situations are Bombers better than any of the alternatives?