We changed "Passport" to "Photograph" in the latest update to avoid confusion. You have to upload those things for the account to be fully usable. Without uploading these, the account will be in "Restricted" state. The reason for this is purely regulatory: Identity and address verification. On ALAT, these happen in under 24 hours.
ID signatures can sometimes be inconsistent with your actual signature. I know I personally struggled with the digital pad when signing for my International Passport.
On the ability to upload, we are working on it.