I was having this same doubt... Used it for a month, but not quite sure if is worth it. Many different opinions about it and the only certain effect is it's algicide properties. Seems to be like a gimmick in the aquarium hobby and since people keep buying it, companies are not ecouraged to prove their claims.
I think a DIY CO2 system will be more useful than keep using "liquid" CO2. There are some videos on YT and the materials are not that hard to get. There are already pre-fab systems to put on soda bottles.