"Who gets cake in their face?" Bet

I went to a wedding last month and by the cake table they had a "who gets cake in the face?" Bet. Essentially the wedding guests put money in a jar labeled "bride" or a jar labeled "groomed" and whoever got cake in their face during the cutting lost the bet. But I didn't understand the point because with a normal bet, you either make or lose the money that you bet but in this case the couple just kept the money in both jars. Has anyone done this or been to a wedding with it? Is it basically just to fund their honeymoon or pay for wedding expenses? If so, that seems pretty tacky to me.