Baking soda tends to be used by moms who have odor issues, sometimes in the wash and sometimes sprinkled in the wet bag between wash days. Depending on the diaper fabrics in your stash, adding a small amount of baking soda to your wash should not hurt anything. It will not likely enhance your washing however if you are already using a good detergent. Baking Soda should not be used as a cleaning agent alone without detergent.
The issues with baking soda come to light when using natural fabrics as it can be slightly abrasive and if your rinse cycle isn’t adequate and any is left on the diaper fabrics, it can be ‘activated’ by the heat in the dryer and eat away at fabrics like cotton and bamboo.
To be on the safe side, help prevent diaper pail odors with the Rockin Green Shake It Up Diaper Pail Freshener instead.