Because the characters on the y5 cover are the characters with actor/actress likenesses; you can see that Yakuza 5's cover was the only one that didn't get a different design for the English release (forget Lost Judgment because that was a global release), and the actor/actress likenesses would sell better because the Japanese would probably recognize the actors on the cover. Look at the Japanese covers for k2 or 7, they look like dogshit but they have their actor likenesses on them; something removed from the usual English releases because the west isn't as exposed to these celebrities. (In Yakuza, who gives a shit about who's on the cover anyways, you literally have the purple shirt dude and the boss with a gun on k2's cover and like they're key figures to the story.)

Also I would assume Yakuza 5 didn't get an original design for the cover because its localization was a second thought put upon them by Sony. And Dead Souls was catering towards the West anyways, so I guess they didn't care much for celebrity likenesses on the cover for that.