Well yes, but actually no. It was extremely important in terms of what it prevented. If the Ottomans had continued to sail unchecked, venice may well have fallen, and further Spanish losses throughout the Mediterranean likely would have been catastrophic. Malta, the Balaerics, Crete, Spain's North African possessions all would have been on the chopping block. If Corfu had fallen, an invasion of Apulia was a distinctly terrifying possibility. Barbarossa's terrifying cruise though the Western Mediterranean in 1544 was never repeated. The shattering defeat at Lepanto also scotched Turkish enthusiasm for naval projects in other theatres, like the Indian ocean
The problem with this response is that it commits the orientalist fallacy of viewing the Ottoman Empire and it’s ambitions during the 16th and/or 17th century as purely militarily expansionist. However this narrative is largely untrue and is one which contemporary historians have been trying to overturn for quite a few decades now.
No, Venice itself and the Balearic Islands probably wouldn’t have “fallen” because there’s little evidence to suggest that the ottomans planned on annexing them. (Not to mention the combined Spanish and venetian naval strength still being an extremely formidable force). Asserting that they did without evidence once again stems from the largely unsubstantiated and now obsolete narrative that they were hellbent on conquering literally everything in the Mediterranean because they could.
The conquest of Cyprus took place so that the ottomans could solidify their hold over the eastern Mediterranean. The conquest of Rhodes and attempted conquest of Malta took place in order to ring the death knell for the knights piracy against ottoman shipping the region. It wasn’t (as I’ve heard some have argued) an attempt to launch a naval invasion of Sicily or something absurd like that.
Regardless, Lepanto didn’t stop Ottoman conquests in the Mediterranean. Since they went onto also decisively conquer Tunis from the Spanish in 1574. The conquest of Crete which happened later in the 17th century took place as part of a separate war with Venice and for different reasons.
You are correct that Barbarossa’s and Dragut’s decisive pitched naval battles,
terrifying but profitable piracy and tactical genius wouldn’t be repeated after Lepanto. But that wasn’t because of the battle of Lepanto, it’s because both Barbarossa and Dragut were already long dead by this point anyway.