According to Microsoft, Bing is using BERT since April. They are using BERT in order to enhance the quality of search results. Bing was using BERT before Google and the usage is also on larger scales.
Recommendation: BERT Gives No Score Or Values To Websites Says Google
Impact Of BERT on Google:
BERT using google is impacting roughly 10% to the search results only in the US and two dozen featured snippets are also impacted worldwide.
BERT Model Optimization: