That's...not how art works. At all. Especially not in a game with that many high paying professional artists as alteil. And especially not in japan.
Alteil's art is commisioned by famous artists with their stamps practically imprinted on them. They do not pay the artist to draw bugs bunny, they pay the artists to draw a new character for the bugs bunny-verse, and most of those artists are free to decline, since they are not affiliated with Gamepot JP/core-edge in any way.
But yes, the artist sells all right by drawing the character for Alteil, and most of them will gladly point this out to you on their home/pixiv page. This does not exclude the artists from several rights regarding his own piece of work as Urizen said.
And for some bonus info; Core edge indeed sells real versions of the card, either as poster (for money) or as...well, this (for 50 point cards):
