I speak only 
So you think that Yandex browser could add something like better auto-translation to Russian language etc?
As far as i know, if you use Yandex search (certainly it will be used there by default) for something casual inside Russia - it will probably give best / one of the best results compared to even Google.
But if you use it to search something anti-government or banned / undesirable by government - it will give you bad results or suppress / hide them…Just like Google for US 
Still, all the above can be easily done with any Chromium based browser, like adding Yandex search, browser itself technically is the same.