It's not the real world applicability that I care about, it's about verifying your understanding beyond just passive observation. It's very easy to give the wro

It's not the real world applicability that I care about, it's about verifying your understanding beyond just passive observation. It's very easy to give the wrong story about something true, but much harder to use wrong story to build something. I hardly care if nobody will gain anything from what you built - I only care that in building it, you proved your understanding. It doesn't even have to be building something useful. Even mathematical proofs count. It wasn't enough to hold a nice story in your head about the behavior of mathematical objects to get a proof - you had to use that understanding to write the mathematical proof. You did something that would fail if your understanding was incorrect - and everyone can objectively judge your success.