The arrows were exclusively fired out of muzzleloaders (I said the breechloaders were light antipersonnel artillery, very different from these heavier guns). The main muzzleloaders were equivalent in bore to European 14-pdr culverin, 9-pdr demiculverin, and 5-pdr saker. Also although these arrows did sometimes have incendiary materials attached, it was not their main purpose.
Sharp-pointed projectiles have greater piercing capacity, which apparently made them more effective than the roundshot the Koreans already had since they were used a lot, at least in naval contexts where these were mostly used, despite the greater amount of energy and resources put into manufacturing them.
Round ball can be used for chain shots, which can be effective at demasting ships. It would be very difficult to aim a needle projectile with the accuracy needed to demast a ship, and it covers a wider area than needle projectile, making it more effective anti personnel shot.
Needle projectiles have their advantages , but their lack of use in other places indicate they had their disadvantages as well. You don't see them used in India, or by the Ottomans, as well as the Europeans. The extra range is a significant advantage, allowing you to engage the enemy while out of range of range of their guns. But storage of the ammunition is bulkier, and cost more, and these drawbacks probably is why most navies did not adopt the needle shaled projectiles.