i have hired this cat to stare at you
Simply put, for covering other threats that Jirachi can't.
It's very slim, but Zard X is probably the biggest reason to use Latias over Jirachi. Latias's typing can also be useful in a pinch, and then it's a bit better at checking Ash-Gren post transformation. I'm okay with a drop to C-, but not really agreeing on unranking.
Also Dragon moves are still used on a rare occasion. Mega Chomp is a big example that was missed in your post, which has Draco to overcome physically defensive Pokemon such as Gliscor.
*Scarf Latiim sorry but this post makes zero sense to me. scarf latias is bad? yes, it is. but this is no argument lmao. you spend 2/3 of the post saying what pokemon use and dont use dragon stab, but cant u just like uh, not run dragon stab on it if that's your argument? and anyway latias isn't a breaker like all of these, it wants draco so it can touch what it needs to revenge kill, so it's already a pretty different situation (and even then like cm said some mons use dragon stab like mchomp and mlatios). on another note, you fail to adress one of the most important traits of scarf latias which is ground immunity and that's honestly very nice in the part you compare to scarf jirachi. you also seem to overlook the fact that mega latias outspeeds scarf latias and mega swampert in rain (even jolly) and can touch mega chairzard x and maybe get some chip on volcarona unlike jirachi which needs a speed tie healing wish to act as a "check", making it a better revenge killer. i'm not saying this pokémon is good however, but you also fail to capture what makes it a lot worse when compared to jirachi, which again makes this post feel very uninformed. lack of defensive utility, that jirachi brings plenty of to the table, and also lack of a pivoting makes it complete tyranitar bait and a momentum sack, which is part of the reason that makes scarf latios and scarf keldeo terrible (not the ttar bait part). all in all, i think scarf latias still has enough of a niche to be ranked, but c- rank could be reasonable.
e: tfw colonel m snipes you
but both of you are right. lati should drop to C-, but not cuz of my reasons.