This team is for maximizing your Geo element, which was buffed a couple patches back. Ningguang will become your main DPS, since her attacks got high damage, especially her elemental burst.
Geo Traveler is there for activating the Geo Resonance, which will buff your Geo damage and shield strength. You can also use Noelle, but her effectiveness isn’t good until you’ve unlocked her last Constellation.
Kaeya and Diona/Qiqi’s role is for double Cryo resonance, which will increase your critical rate by +15% against enemies affected with Cryo.