You can use spreadable butter for baking with however the texture and the final results of the baked goods won't be as good as it would be if you used the correct butter for the baking.
Also the butter with added salt can affect the rising action of the baked goods so I would recommend using non spreadable butter without added salt in baking.
I have tried using spreadable butter before and it was okay and made the food I baked okay to eat however the baked goods didn't turn out as good and the texture was not correct either.
So I now use regular butter when baking any baked goods.
So if you can you should go out and buy some non spreadable butter to have your baked goods turn out properly.