Somebody from the thick ranks of frigate-lovers

please explain to me what's so great about these ships.
They're not the fastest; they're not the strongest; they're very expensive; they seem to give captains a false sence of security causing the loss of a ship. Finally, they are pretty expensive, so the loss does hurt.
I must confess that I don't have a lot of experience with frigates, so my disliking them is more theoretical. I've only ever built one frigate and it sunk on its maiden voyage in the very first battle, despite the fact that it was ordered to pound, had an average cannonier skill of 4.8 and a full load of cannons.
For a big ship, I'd think a Galleon would be better, even though it can't catch anything. A shadowing Schooner can do the catching, while the Galleon can blast anything to bits.
My personal preference is Schooners. Just Schooners. Somehow, these little ships survive longer than anything else I ever tried in cruises. Probably because they run from most combat encounters, yet scoop up all those lovely defenceless merchants, who surrender at first sight. Hey, pirates, not warriors. Preying on the defenceless is their specialty.