Sleep and Wait are two very different things. Sleep is something that people have to do every night or every day for some people who have night shifts at work. People are required to get more than 6 hours of sleep to let the body recuperate from all the things that it has gone through. Waiting is different because you are just delaying the action that you are doing because of something that may occur or because of someone.
You may wait for a friend outside the mall when you have plans to go shopping together. You may wait for your payment to arrive so that you can purchase the items that you need. Based on their descriptions. They are two very different things.