220 rounds per minute, with a capacity of 1,000 rounds, in a gyro-stabilized gun, would make it very effective against swarms of small boats.
Yeah; the OTO Melara 76mm is either 85 or 120 rounds per minute with non-multirole ammo and IIRC it only holds 80 rounds on the mount. The 76mm is better if you’re only going to use it in the surface gun role - not as good for anti-air, anti-missile, littoral swarm or similar uses.
For the US Navy, the VLS is the primary offensive punch, the guns are generally secondary or defensive use only. I think the Navy’s made the right choice of configuration given modern combat factors; better a versatile fast firing, deep-magazined, multirole defensive cannon than a big but slow slugger.