Isso não é significativo do que eu posso dizer. Capas alternativas têm como objetivo adicionar diversidade e criar capas 'raras' que podem ser coletadas e vendidas com um prêmio.
In comic books, a variant cover (sometimes variant edition) refers to an issue of a comic book printed with multiple covers with each unique cover art. Variant covers became common during the "Speculator Boom" of the 1990s, when more collectors became interested in the storage and preservation of their comic books with the goal of future financial gain than reading the comics themselves.
~Variant Covers on wikipedia