That's the jist of it. h3 cells have the benefit of no boundary conditions as all neighbor edges are the same shape and you can only cross boundaries. With s2,

That's the jist of it. h3 cells have the benefit of no boundary conditions as all neighbor edges are the same shape and you can only cross boundaries. With s2, the problem is that four edges are long and then there are four vertices you can cross to get into the adjacent diamonds at each corner. The tradeoff is what you described, s2 cells nest perfectly at different resolutions, but h3 cells are only approximate. They are both great tools useful in different circumstances. It you have to move between resolutions and don't care about movement between cells, s2 is a better choice. If you care only about one resolution for your work or care about movement/flow between neighboring cells, h3 is a better choice. s2 I believe also goes down to a smaller resolution (like 1 cm or so) and h3 goes down to like 1 meter. That said, there aren't many use cases that need greater than 1-meter resolution.