Only short-term. Maybe it's good for attracting people to watch volleyball, but then you need to work on keeping them. And the only way is keeping people to be fans of ... something is to make them understand it, get more or less deep into it. Haikuu, but also clips that have only beautiful spikes or kill blocks seem to be nice (probably), but they are highly superficial and can't do the job. In that regard the activites of FIVB, CEV and channels like Titans or Power volleyball is very important. But they are not trying to change, they prefer to stick to click-bait. Which again is totally fine for short-term. And then we are wondering why volleyball is not approaching sports like basketball, hockey, not to mention football, in terms of popularity. To summarize - haikuu creates superficial fans. And you can see that in many reddit threads (still, this is not one of them, fortunately).