This kit is perfect for a
1. A beginner
If you have nothing this is a great place to start. You could use this kit to do your entire makeup.
2. A back up kit. You never know when something from your makeup bag disappears and you never know what it will be. I leave stuff in hotels all the time. Then I go to get ready the next time and I am missing my mascara.
Think of this kit like a first aid kit. It will get you by with anything you might be missing or you run out of. Maybe you leave the cap off something and it dries out. Now you have a backup for everything.