Prime "detoxifies" ammonia, nitrite and nitrate; it is temporary, and the substances are still there either toxic or not, since it does not remove them. In any healthy aquarium, these three forms of nitrogen will be handled either by aquatic plants, or by nitrifying bacteria and (more probably) archaea. There is no need to be adding substances that "mess" with these. Solve the problem, do not mask it with chemicals, especially when the manufacturer is hesitant to tell us how.
Seachem will not say how Prime "detoxifies" nitrate. I corresponded with them several years ago, and the individual actually told me they did not know, that it was something they discovered in tests. More recently they seem to be skirting this issue, under "trade secrets" or whatever.
Another issue. Prime contains a chemical that binds heavy metals such that they cannot be taken up by plants.
@Essjay has looked into this (she has chemistry knowledge I do not have) and can tell us the name. API's Tap Water Conditioner does not do this, so far as we know. This is why Seachem advise to not use plant fertilizers (Flourish or whatever, that contain the heavy metals iron, copper, zinc, manganese) after a water change, because Prime prevents the plants from assimilating these, so it is a waste. API's Tap Water Conditioner does not have this problem.
I also do not like chemicals like the one in Prime getting into my fish, especially when it is not necessary to begin with. There is certainly no benefit to this.
One of our members, might be
@AbbeysDad has a line (or did) in his signature about clean water not chemical soups being best for fish. My research over the past few years into fish physiology and the impact of various additives leaves no doubt in my mind that my fish are healthier because I do not use anything that it not absolutely essential for the good of the fish.