Is there a source for that?
https://www.seattletimes.com/opinion/with-some-all-electric-...
I happen to live near both of the routes (downtown Bellevue) that have already been electrified, so it already seems like a huge thing here, even though they are just getting started.
(Incidentally, the same thing was true in Beijing when I lived on their first battery electric route 7 years ago)
It's about the Chinese government investing in electric vehicles to make them cheaper long term and increase their viability and usage.
China has public transportation everywhere of course, though you’ll see these buses in shanghai and Beijing but not yet in tier 3’s (at least last time I checked a couple of years ago, it will change eventually).
https://www.weforum.org/agenda/2018/04/china-is-adding-a-lon...
The sources you provided didn't say anything about that. In the meantime:
https://qz.com/1169690/shenzhen-in-china-has-16359-electric-...