pirates used sloops to attack tradeships because they were faster, they would steal provisions to remain at sea and would extort valuables and other loot from the traders. they usually didnt capture the ships and attempt to sell them and their cargoes because it meant they would need buyers who tended to shortchange them and also as with what happened to bartholomew roberts their success could lead to merchants ceasing to invest in dangerous waters. thats essentially why roberts went to west africa after completely dominating the americas. (he was killed in africa and his crew captured and executed)
technically frigates were historically used to transport marines into conflicts on sea and on shore. armies weren't actually transported in bulk until the invent of the steamer as was what happened with the boer wars and the great war. britain and france may have had global empires but usually it was a small minority of officers and noncommissioned officers using locally hired auxiliaries to govern lands that technically were not conquered by vast armies but was actually acquired using diplomacy, tricks and the threat of naval bombardment.
they lost their empires as soon as the "game was up" as we english like to say, and the native peoples realised britain was not determined to ferry huge amounts of soldiers to fight over resources they could maintain a monopoly on by controlling sea domination.
essentially they returned power to the natives but even to this day they continue to have naval supremacy. on condition that the native nations maintain the flow of produce for trade the western powers dont interfere in politics while the natives are expected to remain indefferent to their coasts being patrolled by foreign powers.
whicj is why china in our time is being aggressively targeted by america, japan and their allies because if they lose the south china sea then china will dominate the indian ocean and all the trade that exists along the suez and the cape and the pacific.
the only war i know of in that era that genuinely ferried armies across a large body of water was the american revolutionary war of independence. many of the british soldiers in the americas were actually from america because despite modern american belief many of the americans in that time were staunchly british, they just happened to become republican due to taxation and restrictions imposed on them on trade. the cause if the war was that they felt like they were second class citizens despite considering themselves british. it was their bitter feelings to the crown that made them rebels. many of the soldiers trying to subjegate the republicans were also from the americas and when regiments were sent from britain they were sent with the royal navy because the french who with napoleon were also republican were supporting the americans by provising them with weapons. the french also harassed the british supply lines.
so what i am saying in length is that actually, there hasn't ever been a large transport of soldiers across water to a foreign power successfully until ww2. D-day is essentially the first major amphibious assault that was successful.