I wouldn't use it "instead of " the bottom either. I would cut out a circle from cardboard, cover
it in foil and then tuck it into the bottom of the springform and fill and bake your cake like normal. then, you can slide the cardboard and cake off of the metal bottom when it's cooled. If you use just parchment, you can leave the bottom a bit bigger and have the ends come up the sides of the inside of the pan a bit. after your cake is baked, you can peel down the paper and use it to slide off of the metal bottom onto a disposable plate. then trim the paper away.Or, if the parchment is cut the exact size of the bottom, you should be able to work a thin pancake turner under the paper and then ease your cake off the metal bottom onto a disposable plate---if the cake is well cooled. Just some ideas.