You will capture Curio DNA randomly during battles. This gives you a chance to replicate and gain the Curio if you spend regular coins or always get it if you spend premium currency. Unlike the Discs that you can get in the Shop, you will know exactly what Curio you will get and pay less per Curio. However, if you spend regular coins you run the risk of not replicating the DNA successfully. Do not use the Curio DNA when you already have that Curio and do not need a new one.