I support their anecdote. Any "supplements" that have significant effects are highly regulated and somewhat risky. Worrying about things that will make a 1-2% difference isn't worth the time, just workout one more rep.
It don't work like that.
The amount you can work out (at intensity) is limited by your recovery time.
Thus you take that "supplement" and can do one more rep, or go to gym extra time a week, especially if it comes to "regulated and risky" supplements, then you can do many, many more reps.