I have subbed in applesauce in some quick breads/muffins in the past. To me, baked goods tend to come out a bit less fluffy/springy, but it's tolerable for the first day. However, texture, moisture, flavor, etc all go south really quickly and by Day Two it's dry / leaden city.
Ironically, I was just making a chewy ginger cookie recipe from
Ready for Dessert a couple of weeks ago that called only for applesauce. I actually subbed oil back in. They turned out great!