Why missiles on a carrier create flight-deck tradeoffs

Why is adding missiles to an aircraft carrier not a simple self-defence upgrade?

Launch arrangements, blast safety, ammunition systems, and training can interfere with flight operations, so the change affects the carrier’s central purpose as an aviation platform.

Missile launchers must be positioned so blast and fragmentation do not damage or obstruct flight-deck operations. Deck-level launch can require a foreign-object inspection before aircraft operations resume, while lower sponsons can demand structural changes and increase ship width. Ammunition handling, altered storage, system integration, and crew training all take time and money. A carrier's first purpose is to launch and recover aircraft, so self-defence changes must protect rather than impede that mission.