Well, you need a good boxart to sell your products better. Having a plain, unappealing boxart makes it less appealing for the consumer, and therefore, if the consumer is uninformed about the product, they'll be less likely to purchase it. I'm doubting that this stock image will be the final product, though, as Mario Party boxarts are always good. Even the worst boxart, Mario Party 10, is still very pleasing to look, and I actually do have expectations for a good boxart.
As for the game itself, I don't have much expectations for it so far but I'm open to see how it'll turn out. I would prefer the older Mario Party formula but if the game itself turns out to be good and fun, I'll welcome it.