I think it refers to more prolonged use. Whenever I've looked for solutions to fin rot I've always found aquarium salts being an essential part in the treatment, and it worked wonders for my betta when he had it. And then using stress coat after to aid in the regrowth.
Also I saw melafix mentioned somewhere towards the beginning. I would advise not using it. It may be designated for fin rot and other bacterial infections for fish, but it is not good for bettas. Melafix usually contains tea tree oil, which is meant to help the fish in melafix, when in reality for bettas it has shown to coat the labrynth organ and can essentially suffocate your betta :/