I know this is going to be super controversial, but I genuinely find illustrations of mathematical concepts below a minimum threshold of complexity totally useless and frequently detrimental.

Below a certain level of complexity the human brain is much faster and efficient operating on abstract symbols, like 'x' and 'y'. You can solve equations and figure things out in a fraction of the time it takes you to visualize bananas, goats, coins, bread, milk, etc.

Visualizations have a role in developing intuitions about complex structures, such as what the a matrix does to a vector or what cosine similarity means, and so on.

But in recent years, everyone and the next man has suddenly assumed that visualizing the number 1 or 2 in terms of every day objects somehow helps learning. It doesn't.