It is ok in moderation. No more than three times a week, maximum. Once a week as a treat is ideal.
Weruva's fish recipes are the only ones i feed to my cat, as they constantly test for mercury, keep low mineral levels, and use sustainable wild caught fish. It's definitely better than most fish recipes but should still be limited.
BFF is fine but you should only feed it once in awhile, say no more than a few times a week or less. The same goes for any seafood based canned food. Some cats get addicted to eating fish and will refuse to eat anything else, seafood tends to be low in protein, some types of fish may contain traces of mercury, cats who are prone to urinary issues may develop issues when eating a seafood heavy diet.