I don't think the repetition is a problem. He's using a local model for human-assisted writing with pre-generated embeddings - he can use essentially an arbitrary number of embedding calls, as long as it's more useful for the human. So it's just a question of whether that improves the quality or not. (Not that the cost would be more than a rounding error to embed your typical personal wiki with something like the OA API, especially since they just dropped the prices of embeddings again.)