Using backticks is not the only way of avoiding the shell. Pass a list to system (or to a three-arg pipe-open for convenient output suppression) and you get the same effect.

So no, this isn’t a reason to use backticks in void context; it is merely a reason to avoid invoking the shell when you don’t need it. Even if backticks were required for that, saving a couple of microseconds here and there wouldn’t constitute a good reason to do it, as per the topic.

Makeshifts last the longest.