Hmm. Taking a sword to the sternum or deflecting the sword into the soft, unprotected belly? Decision, decisions...
You misunderstand, it is in regards to vertical strikes, the previous one that was purely for aesthetic, has a gap there, and was rounded with le boobs, hence why any strike between the nipples would be directed into the gap directly into the chest. While the new design which is more in line with actual armour (how female armor was actually designed) has a point.
Aand thus any strike gets deflected to the sides, not below because well, it would have to go through the armor to get there, only a horizontal strike would go there and well, such a strike wouldn't even hit the chest anyway, unless you tall af.
Side note, this design also has the benefit of air being behind the armor in the centre thus redirecting the pressure of any blow to near the centre to the rest of the chest, instead of the centre absorbing the impact (which would shatter the sternum btw). is why a lot of armor design is somewhat pointed in the centre, to distribute the pressure from hits.
Anyway is demon lady that has magic and is powerful and shit, so logic with her armor isn't exactly needed
but yeah, wouldn't go to the belly would go off to the sides missing them entirely. like you would have to pull the sword back as you have struck them for the sword to go down instead of the side... which well... momentum says no.