Very true, I would say. It is good to be persuasive, persuasiveness as such is a virtue, but that does not mean that that which is persuaded for is always good, nor that it is always good to be persuaded.
Likewise we can say that unpersuasiveness is not necessarily a vice, because it is not always bad to be unpersuasive. For example, if someone has very bad ideas then it is in their and everyone else's best interest that this person not be very persuasive.
Persuasiveness is just the way in which arguments are formulated to produce agreement and/or understanding in others. Rhetoric as an early form of marketing.