What does the Xiaomi Home Secure do when using the Xiaomi Smart Camera C300?

Save the recordings to the cloud with the Xiaomi Home Secure. This option offers you greater security and backup. However, it requires a subscription. You can opt for a limited free plan or a premium one with more capacity and features.
Note:
The Xiaomi Home Secure purchased within each camera is only valid for that camera, and multiple cameras need to be purchased separately to open the Xiaomi Home Secure.