Brawl Stars events are different game modes that the game offers. Each event has its own rules and different maps. Ranging from simple ones like Gem Grab, Showdown, and Bounty, to more intricate ones like Heist and Brawl Ball. Events are your main source of Trophies, as well as daily quests.
Since events award Trophies, there is always a need to do them. Buying an events boost will get you a professional player who will achieve a number of wins of your choosing in one specific event. This can be used to farm Trophies (although, we would suggest our Trophies farm service as it would be much more efficient), complete some daily or special quests, and such. In any case, you can never go wrong with buying such a service for Brawl Stars, as the trophies alone are worth the investment.