Ikara is a one shot affair. With a rotary "drone" you can go back to the ship, fit another torpedo, and have another go at the target or a different target at a later time. You can fit a lot more torpedoes by themselves in storage than you can Ikaras.Aye, the reason I suggested Ikara was a compliment to ASROC, as both I think have a range of 10-12 nm or so. But a modern version of Ikara with a turbofan I’d have thought could push out easily to 50-100 nm, and indeed cover that distance at around 500kt making it much faster to react than a rotary asset.
Your second point would be a key limitiation though, I was thinking purely in terms of the attack.
Also as mentioned by another poster, the unmanned drone can do multiple different jobs by fitting a different payload underneath.