@FanPoke was slightly right in how he said it makes your playthrough easier. But say it is the Legendary Birds or Beasts. Those aren’t incredibly powerful, and those won’t bust your playthroughs. And you said ”looked down upon”. I wouldn’t say that. I think every fan has their reasons why they don’t use a legendary. I will list the most common ones for you.
The Legendary is at the very end of the Playthrough, like Mewtwo in Kanto or Zacian in Galar.
The Legendary is very powerful, and you can get it before the Champion Fight. So people don’t use it, like Eternatus in Galar or Necrozma in Alola.
You simply just won’t come across the Legendary with purposely looking for it. An example is Articuno, you are most likely not gonna wander that deep into Seafoam islands.
They care about type overlap on there team. Say in Johto, you pick Cyndaquil, and Ho-Oh is the legendary you find. Most players won’t take their starter off for a Legendary.
The Legendary requires effort to obtain, and the player doesn’t want to use their time on that. Like on of the Legendary Beasts, or maybe a specific legendary in Ultra Wormholes or Max Liars.
And finally, the final reason and the reason I don’t use legendaries in playthroughs is just some kinda mental rule that the player just kinda agrees on. The rule is not to use legendaries.
I think that is all! Now, you said people as a collective group. I think you are wrong there. More people use legendaries then not in playthroughs. I personally used Eternatus on my Shield Team, and later put Zamazenta on it once I could. But I think those are the reasons people don’t use legendaries on teams.
Hope I helped!
