How are Sparkling Cubes given at launch?

That matters because a Sparkling Cube is a premium Anipod, and premium Anipods guarantee the captured creature comes out as a shiny glistening variant. Normally you pay for that certainty. A Sparkling Cube costs 1,500 Glimmer or premium currency, and the currency route means buying 100 Sparkling Crystals and exchanging them at an Outpost vendor. Handing them out at launch means every player gets guaranteed shiny captures without touching that chain.

So the sensible move is to hold them. A Sparkling Cube spent on the first thing you meet does exactly the same job as one spent on a creature you actually want, and the second one is worth far more. Work out what you are hunting before you throw.

What else the launch rewards include

Cubes are not the only thing arriving free. The global launch rewards also include eggs, among them a free Perfect Egg. Separately, logging in daily during the pre-launch event grants three eggs to incubate, so if you are around before launch you can start with incubation already running and then collect the launch batch on top.

Not settled: How many Sparkling Cubes each player receives at launch is not fixed publicly, so plan around having few rather than many.