For me, the vertical seams provide such nice support and a rounded shape. I feel quite secure in this bra, and it's really pretty, too! This G cup is juuuuust on the edge of being too small, but it works for most days.
This is a very strange bra. The outer layer is seamed like a balconette but the inner layer is a 3-piece half cup. I'm not sure what the purpose of doing that was. It spreads out and flattens my breasts against my chest wall and also sits very low. It does feel very comfortable, but the shape is very bad. This is definitely an attempt at a bra to give cakes-on-a-plate cleavage but it doesn't give me much. This is probably the least projected my boobs have ever looked in a seamed bra. Perhaps if you want a sexy minimizer this one is for you.