There at the end he revealed the point of the exercise; it wasn’t to have a functioning disk, but to push one’s individual skill boundaries and learn new ways to solve problems. If the disk worked at the end then it would be a double benefit, but that wasn’t the point.

It’s a lot like learning to fly or sail a boat. Are there more economical means of travel? Absolutely. But in doing these things we gain new tools to solve adjacent problems.

Do I have a need to finely and evenly spread a magnetic slurry? Nope. But the wire-wrapped rod may very well help me out in the future!