I think I would still rather use booster because of the aforementioned extra moveslot and the fact that you can just switch in Iron Moth whenever you need (unless you get roared or whirlwinded and as far as I can tell the most viable user of that is Moltres). Still though I appreciate how you did show that there are advantages to using meteor beam. In theory you can get both boosts in electric terrain but electric terrain sucks this gen for obvious reasons and you lose the boost after electric terrain ends anywayI did say it was niche lol
The main benefit is that you’re not locked into cashing in your boost on your first switch-in. Besides that, it gives you a oneshot on Cinderace, Moltres, Dragonite if multiscale is broken even by 1hp (or if already at +1 from fiery dance it’s a roll through multiscale—the most practical implication this actually has is that fiery dance into meteor beam kills, whereas booster fiery dance into dazzling gleam is an unlikely roll without the fiery dance boost even on no-bulk sets), Zapdos, Araquanid, and Kyurem, all of which live any booster spatk hit. That includes rock tera blast, btw, unless you’re Moltres or Cinderace.