You do not understand what Citrea is doing.

They're not storing data or committing data. They're provably publishing data. They need to do this because their protocol needs to ensure that other actors in the protocol get that data in the non-cooperative case.

Lightning does the same thing: if an HTLC transaction goes on chain, collecting the HTLC forces you to publish the pre-image on the chain, ensuring he next person in the path can find the pre-image and use it themselves to collect their HTLC.

🎯