Xink only asks for an email which has Super Admin rights in your G Suite account, nothing else.
Super Admin passwords are never entered in Xink.
We only need the email address (ID) to verify who has access to the retrieve the email signatures stored in Xink.
How are permissions to Xink granted?
Permissions granted to Xink service are controlled in Google’s panel described in this KB article.
Admin rights are not grated to Xink.
Who is updating the signatures in G Suite?
The updates are made by the Super Admin user i G Suite completely outside the Xink environment.
Xink does not have access to update the signatures for each Gmail user.