Why football players boots have spikes their sole
Give short and sweet answer​

it helps with balance and speed.

"The football shoes have spikes or studs because the studs or spikes provides larger frictional force than normal shoes while running on the grass. The studs prevents player from slipping on the grass and help to run faster and change direction quickly without slipping"

they provide a larger frictional force than normal shoes while running on the grass.