In most Freeze teams (especially Ayaka / Ganyu teams), Shenhe is a decent upgrade over Rosaria and Kaeya. While Shenhe has a longer Elemental Skill cooldown, in most rotations Kaeya and Rosaria aren’t able to use their Skills more times regardless. Shenhe also brings much more in terms of buffs, which makes her a better pick in most cases. It is worth mentioning that Shenhe, Rosaria and Kaeya perform similarly in Reverse Melt and Physical teams.