I couldn't think of a reason
Hey that's ~30/year in savings! Almost 1/2 the cost of a PS234!!

But...I've been doing some research and.. found out that many offensive odors in refrigerators are organic acids and these would react with sodium bicarbonate (base) to make H2O and a salt. So it does indeed get "used up".

However one cannot possible "use up" all the Baking soda in a box when used for odor control (can stretch its life by stirring it up) so long as the salt that's formed is harmless to pools, we're still good to go!

Been a slow Sunday...

http://www.madehow.com/Volume-1/Baking-Soda.html
http://www.madehow.com/Volume-2/Bleach.html