Some collectors chase after the Cosmos holofoil aesthetic due to the unique and non-standardized patterns that tend to develop. Additionally, Cosmos holo cards will occasionally include distinct Special Features in the form of Swirls and Crosses (X-shaped) within their holo patterns. The statistical occurrence of just one Swirl or Cross (X) being present and visible ranges from uncommon to rare as most cards don't display either one. This rarity can be exponentially increased when multiple of these Cosmos holo special features happen to be visible on the same card.
Using some creativity, the Pokémon character artwork may even appear to "interact" with these Cosmos holo special features; however, this claim is typically subjective and depends on each person. Examples: Pokémon standing on a Cross (X Marks the Spot) or standing on a Swirl (Bullseye); Pokémon spitting, firing, or grabbing a Swirl. Statistically, based on PSA's public Pokémon card population reports, these foreign (non-English) language variants are significantly harder to acquire than the renowned and adored original English Base, Jungle, and Fossil set cards. Feel free to contact me.