I want to explore the negative polarity.

[Ohr Ein Sof]

To realize that fear is useless is one of the most important  things to come to accept.

I agree with the sentiment(though not the "semantics"), but in the end, nothing is "useless". It's only useless/detrimental if one lets it rule and dictate. Fear is telling somebody something about themselves. It's the question of how to interpret/apply the lesson without giving into the fear itself. Fear is just a temporary stepping stone to be honored and integrated and purified to move to the next stepping stone on the path. One can't hide from it, or merely discard it as useless. It's a little more nuanced than that...but yes, I get your point. When fear is allowed to rule and dictate, it's absolutely counter-productive.

It is both useful and useless. Just depends on the entity