Latias has checks, but not counters, trick cripples chansey, surf/draco nuke krook, no pursuit means specs is free rain, Life orb means it can use its coverage to KO, Grassy seed means it can CM out of control given the oppurtunity. Latias also defensively and offensively a large chunk of the meta to the point u see megahorn bulu to otherwise not be walled which speaks to how latias is taken defensively. Latias having 110 speed makes it fast, faster than terrak, speed tying with lycan dusk, and outspeeding ada gyara at +2 with a scarf. Life orb has not switches besides chansey. but chansey is easily taken advntage off, and without eviolite, it falls easily. Like You can name soft checks celesteela, jirachi, scarf krook. But then u also have to remember that either they lack recovery, can be taken advantage off, or are generally not a defensive awnser and have to be brought in via doubles and pivot moves.
The awnser is, I would like a lati test, as in the viability rankings "you can easily replace a mon with latias and it will have success or do better"