Larissa has a unique style for performing her deads. She does a "Sumo Deadlift." Sumos are done with knees outside of the elbows. Some find it easier on their backs - especially tall folk.
Tall folks have longer thighs which put their center of gravity further back from the bar during the initial lift phase of the DL. The further back you are from the bar, the more stress you are putting directly onto the low back. To counter this, it can be helpful for those with longer thigh bones to spread the legs "Sumo" style to get your center of gravity closer to the bar. This can help prevent/relieve back pain and keep your back healthier.