Checkpoints are a core functionality of WOS. Obviously, they save the players position when they reach it and they respawn there if they die. There's a few more things too...

Animations

Checkpoint animations are a cool thing that shows players that they've reached a checkpoint in a pleasant way. Checkpoints animations are handled on the client side, meaning there is almost no delay before the animation plays and they are not affected by ping. There are a few animations: Classic, color, rotate, and some other variations.

Saving

Checkpoints save when a player leaves the server, and loads back in when the player joins back.