Do Sparkling Cubes guarantee shiny Aniimo?

That turns shiny hunting into a spending decision rather than a luck one. You do not grind encounters and wait for the odds to land. You pick the creature you actually want in its glistening form, throw a Sparkling Cube at it, and that is the variant you walk away with. The scarcity has moved off the creature and onto the Anipod.

And the Anipod is not cheap. A Sparkling Cube costs 1,500 Glimmer, or you go the premium currency route: buy 100 Sparkling Crystals and exchange them at an Outpost vendor. Both paths are a real outlay, so the sensible habit is to hold cubes for creatures you intend to keep long term rather than spending one on the first thing that looks interesting.

Free cubes at global launch

Sparkling Cubes are handed out as free global launch rewards, so your first glistening catches cost you nothing. Decide what you want to point them at before you start playing, because once the free ones are gone you are paying the Glimmer or Crystal price for every one after that.

Sparkling Cube or Anipod Ultra

These two premium Anipods solve different problems. An Anipod Ultra guarantees the capture of a wild creature and ensures at least Elite potential, so it is the one you throw when you care about what the creature can grow into and do not want to risk it getting away. The Sparkling Cube is the one you throw when you care how it looks. Choose based on which of those two things you would be more annoyed to miss.

Not settled: Whether a Sparkling Cube also locks in the catch itself, or does anything for potential, is not settled. The only guarantee attached to it is the glistening appearance.