The Territory of White Lotus Sect was located in the cold region where the snow was the main element of every scenery. It was also a great place for mastering Water Qi and its variation which was ice. There was no Ice Qi so if someone wanted to have ice arts in their arsenal they would have to master Water Qi first.
For most cold beauties who wanted to follow this path, White Lotus Sect was the ideal choice. They could train, far from any disturbances and desires which could halt their training. This was also the reason why one needs to be a virgin to enter into the sect. Only when one's heart is pure can you focus your time entirely on training.