Even more than ten years later I still love these last two episodes so much. Quinn insists in an early episode that Sarah only fell for Chuck because the intersect ended up in his head. This final storyline answers that question for the audience and proves quite effectively that they are supposed to be together. The intersect is the thing that put them in each other's lives but falling in love that was their own choice. It's not a perfect ending but I think it really does a lot to leave Chuck and Sarah in a hopeful place.