What is the point of the pct in MLB baseball?

Hi, I am not really a baseball fan but I like to see if my hometown team is winning and thisyearthey are for the first time I. Forever.. ( the pirates lol ) but they just got a .500 pct is this stat something necessary for them to make the playoffs or is it just a random number.. Cause my friends wh plume baseball more thanme were like o please get us to 500l and last night they did so is this significant to the postseason or just significant for "bragging rights"