i would think to give these artist the chance to get there drawings out there are to get them well known to other dev's. hard's to say really.
I highly disagree, honestly
Having multiple artists is fine, and yes, it can promote them, some games do that and it works (like Monster Girl Quest for example)
However, when you put 5 artists basically against each other, by making the player choose which artist he likes from the beginning, with small pictures as examples, and with no way to change it afterwards (as far as I know), it does not really promote them
In fact, I would like to believe that most players selected the 3rd artstyle (aka SethxZoe), because it's the most "modern" and polished
Also, it's quite hard to actually find the artist names, since there's no credits anywhere (as far as I know), so you specifically have to go to the arts gallery, select CG scenes, go to your specific artstyle, and finally select one picture to have the popup that says who drew that
Whether it impact the development time is hard to know (even if I do believe it does), however, it's still a huge waste of money, and it makes the game even more of a mess than it already is