no they work differently. The banna leaves soften the tail so that the betta( especially young ones) can spred it more. The ial make the water anitbacterial, lower the ph ,harden the bettas scales, encourage breeding, make bubble nests stickier . you can use them all the time. My breeder freind uses them in all in all his bettas water ( I am talking about 100 bettas) and he says he has had no sick bettas .
here is a link where you can order some. I know they do not sell them in stores cause the best ones are the ones that dry naturally and falll off the tree and need to be collected by hand. that is why you usually have to obtain them over the net, or in my case I have a freind who's nephew in law in malaysa collects them and mails them here to the US to my friend. He sells the small packs for $5 which includes the shipping. here is a web site that sells them
http://www.siamsbestbettas.com/order.html. They are supposed to slightly tint the water. I use it all the time and it does not tint it that much. If you ial do not tint the water then they may have already been used.