Why does the LOL jungler keep minions?

Usually, a monster with a red and blue buff will be left. That monster costs 5 yuan and then put an eye in the buff grass so that the opponent's jungle hero may come to the jungle and cooperate with the mid lane hero to predict him. You can hunt and kill along the route, but this can only be done in the passerby game. In general, high-end games are filled with eyes, which will not allow you to steal the buff. Even if you steal it, you will not be able to kill the opponent's hero. Also, if the mobs are there, the system will not refresh. The buffs there can affect the opponent's jungle gank rhythm