We've used carriers a few times, but land based air will usually get there quicker, cheaper, and will offer better capability once on scene.
We've needed carriers just once in my lifetime - and that was in 1982 - more than 27 years ago.
Do you need more of a definition of niche than that?
OK: Those capabilities that we need every time we go on ops are core - those that we seldom need are specialised, or niche.