A visualization of the surfel graph from overhead. It looks like a bunch of colorful mushrooms. The distance of leaf surfels from root surfels is erratic and unbounded, though it is usually somewhat close to twice the diameter of the root surfel. Maybe not a good pick for an acceleration structure.
https://cdn.masto.host/mastodongamedevplace/media_attachments/files/113/338/056/700/529/829/original/7a81e511eefc622a.png