Here's the thing, though. Just coding a game is a lot, before worrying about actually designing mechanics and managing meta-progression and writing even a basic story and world building, etc.

Making a fan project is real, concrete experience. It allows you to focus on one specific thing (actually writing the code and managing the codebase) without focusing on all those details. There's a reason most programming courses involve making simplistic clones of stuff that already exists. Many game development classes/tutorials do exactly the same, and work you through a clone of some other, pretty simple game.

That's what a fan project like this is, but it lets you focus on how a game larger in scope manages all the same problems instead of how to do it in brick breaker or whatever. It's valuable experience that's hard to replicate on a smaller project, and it's how some people learn best.

Others absolutely will do better starting small and just iteratively building up forever, but it's not the only way to learn. This approach is legitimate and for many people, better.

Now advertising it? Not a huge point of that. Unless you're actually asking people for feedback (how did they solve this problem?) and learning from example that way, you don't gain anything from telling people about it.