Xiaomi doesn't provide the kind of network infrastructure that Huawei does. So they don't have access to the kind of data that concerned us policymakers.
If everyone start using their phones, they kind of will. I would guess it's easier to spy on people when you own the hardware and OS. Maybe the infrastructure would allow broader spying but owning a big part of the smartphone market allows for more in-depth spying for those with Xiaomi phones.