It looks like the rollout is only for users from India. This tab was announced in December at the “Google for India 2022″ event in collaboration with the National e-Government Division (NeGD). It also talked about integration with Digilocker, but so far it’s not available.
The Important tab is a safe place to keep important documents like your passport, Aadhaar card, or PAN card. You can copy details from your documents straight from the app, which makes it easy to enter details like your PAN or passport number into online forms. You can also search the Important tab for your documents or filter by category.
However, the Safe Folder still remains. The Important tab is biometrically protected or device-locked and is intended for convenient document storage, while the Safe Folder allows you to set a custom lock key and is intended for all files.