I personally don't, and don't even use a cover for my comic unless it's gone to print. I find variant covers are better for bonus material, or if your work is especially coveted, makes for fantastic promotional items. I also feel that unless your readers are familiar with the pop culture references, folks might miss the significance of it.
Like, personally, I'm not really sure what you're referencing in the covers you posted (the art is superb though!), so... 