I feel like this isn't even a particularly new thing. I worked at a medium-sized SaaS company and we did disaster recovery drills for moving our stack from eu-west-1 to eu-central-1 in case something catastrophic happened in Ireland. If you want HA, you kinda have to assume that any single country in the world can have some kind of a crippling disaster. Unfortunately for Yandex's clients, Yandex only has regions in two countries, and not that many regions either.