I don't look at it this way. The oven and all 3 recepies are unlocked from the very beginning, so the goal is really optional. The benefit for completing the goal is you get a 48 gem decor for free. So it's like you exchange 23k gold (if 3squares' calculation is correct) and some hard work for 48 gems, which to me sounds like a very good profit.
Of course, if you don't even like the final prize and are tight on gold, just don't do the goal. Nothing loss