Why was /ALL chat made for?

So when I end up vs my cousin in a ranked game I can talk to him. Friendly banter is worth the chance of toxic happenings.

Oh, and also: to get the enemies to feed the poros on ARAM.

To harass and to send i love you letters to yourself.

Obviously, even a PhD(The D is for dumbass) wasn't enough to figure out that a game where you succeed off of destroying others wouldn't lead to people bragging and being nasty.

Dash was bored and had the keys to the camera room.

Wait, I might have misunderstood the question.

Getting casuals to invest more mindless time into LoL so they feel more compelled to buy new things.

. . . . . . Oh, you meant the chat function, not the little show Riot puts on...sorry, can't answer that

As another form of league news and entertainment to advertise events. That's why they talk so much about art, cosplay, and champions/updates.

To let out a few BMs when playing a tanky toplaner to tilt scrubs.