Hi Kartic, the key in the anti piracy roles are not the vessels itself, but the helicopters and comando forces! A missile boat don't have helicopters normally and corvettes often don't have the range and endurance for these patrols, unlike frigats.
An LHD instead has much space for comandos, not to mention also to imprison the pirats, but as I mentioned above to carry much more helicopters and cover a greater area.
For NATO it might not be important, or cost-effective to send such a big vessel in these areas to fight pirats, but if IN wants to be the major navy in the Indian Ocean, we should give a clear sign.
