Its no secret that phones in China cost less than they do outside of China, which makes it tempting to import one. Heres one more reason not to: Xiaomi has blocked the installation of its Global ROMs on its China-bound phones.
MIUI in China replaces Google services (which are banned in the country) and has other tweaks. Gray import phones (bought in China on the cheap, but used elsewhere) usually have a way to enable the Play Services, but they still feature a bunch of Chinese apps and services that you won’t use so it’s basically full of bloatware. The Global ROMs were specifically tailored for markets outside China so they only have the stuff you would need and no traces of Chinese writing anywhere.
So far it was possible to switch from one to the other after you’ve purchased a phone, but that’s about to change now. You will no longer be able to flash the Global ROM on a Xiaomi intended for the Chinese market, nor the Chinese ROM on a global phone (which some did to get updates quicker).
There isnt much clarity as to what extent existing phones will be affected (it seems to be a MIUI 10 thing). There are reports, however, that you can flash whatever ROM you want on phones with an unlocked bootloader. Still, as you can imagine, people in the Mi forums (Source link) are pretty angry about this development.
Going forward, Xiaomi recommends that you buy phones from its official stores or from authorized retailers.
PS. For non-Xiaomi phones the usual issues remain you may have to pay import tax (negating the price difference) and theres no local support.