Well I don’t use cookies on any of my sites because I don’t like them at all and don’t see why you should have to put up with them.
However, WordPress uses them and to use WordPress as my blog software I have to put up with them being presented to my visitors.
From what I understand WordPress uses them to remember the logged in users and commenter’s details so they don’t have to enter them again and for no other purpose. I don’t use them for any other purpose.
Feel free to block them if you wish.