It's official

For starters, Pyke is a very popular champion so it makes sense that he would get some more attention than someone like Ivern.

Secondly, two of his skins are in a series of which all the participants received chromas. Blood Moon Pyke got chromas just like Sivir did and BM Aatrox got his prestige edition. In this line of PROJECT: skins, everyone has chromas or a prestige skin, every last one of them.

Finally, Riot is just adding more chromas in general. Technically speaking, Neeko, Yuumi, Sylas, and Qiyana all only have chroma-skins as well. It's a new thing they're doing which is good because it gives players more options and it takes almost no time at all for Riot to create so they can sell it at a very cheap price. It's a win-win.