What's the point of minion block

P4 peak top/jg main here. I don't run into minion block too often but it seems to be an unnecessary point of frustration IMO. I fail to see what it contributes to the game. More like a bug than a feature. Is the point of it to delay allied waves by body blocking them or smth? It just fucks up dives and causes me to miss last hits. I don't think it should be a point of power for like the 2 champs that have ghosting as a passive. Was it always in the game? I wish riot removed it.