That is a neat design. From what I can tell though, the split base/top is overly complex. You can simply set (in PrusaSlicer at least) the number of layers to print normally before switching to vase mode.

Other than that, it seems to deriving strength from having sides that are not flat (same reason a rolled up paper is stiffer than a flat pice of paper), a fairly common trick when working with thin flat material of any kind (e.g. bent metal or cardboard have the same concerns). No "unusual" vase mode tricks that I can see.