Yandex taxis are only popular because they bought and extinguished Uber in Belarus. They're much worse in terms of quality of the service, people only use them because there isn't much choice.
"On 13 July 2017, Yandex.Taxi and Uber signed an agreement to merge their businesses and operations in Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, and Russia. ... Yandex invested $100 million and Uber invested $225 million in the new structure."