Okay, have you ever tried to "become better" to the point you researched what would be needed to have a custom PCB built with all of the components on a stock Arduino and any additional shields you might use? You'll see that you will need minimum orders. You'll also have a much more difficult time creating the PCB, as you'll have create all of the traces to connect everything. The method chosen allows for off the shelf components with a much more easily created PCB with minimum traces created connecting pins from shields/LEDs/etc. These will be dirt cheap and can be order in tiny quantities.

This is also a hobby project. To custom build a PCB with all of the components brings this into the Kickstarter world of something. So the person can buy <5 PCBs to play with as hobby or attempt to fund say minimum 500-1000 pieces. From TFA: "Important Notice: This is just a fun project, it was started to pass the time, it is not at all professional and is not intended to be. Is not an alternative for professional device."

Even with the method chosen, if you think the person did not become better after making the simple PCB or any of the other coding required, you're off your rocker. Every build like this comes with mistakes and learning how to correct them.