Adding baking powder to a recipe that calls for baking soda is ok. Adding soda to a recipe that calls for baking powder can cause issues since baking soda needs acid to activate-- there will be little rise and the flavor will be off since soda tastes bad when baked and acid has not neutralized that taste.They are pb cc. They are poofier, but I am told they taste the same.
Poofy cookies can be good too!