The Paris Tarot also tends to make clear that one typical place you find an extra bestial face on the Devil in these images is in his crotch; they seem to want to emphasize the consuming nature of his sexuality. By contrast, the Conver Devil could be read as androgynous, with both breasts and male genitalia, clearly depicted.
Now, the usual source for the depiction of the Devil as horns is typically taken to be Pan; this Roman mosaic could easily pass as a portrait:
On the other hand, while Pan typically has
horns, Cernunnos specifically has
antlers:
The Cernunnos image seems to be made to deliberately establish kinship with the deer, whose antlers are almost identical to the God's.
Now, the horns on the Tarot of Paris Devil are rather subtle, but he does seem to be wearing a beret of some sort. In the Conver Marseilles, the Devil definitely has antlers rather than horns, and they seem to be worn on a helmet or bonnet. Perhaps some kind of theatrical costume or horned helmet is meant to be portrayed?