It would be useful to allow signers to see attachments before an envelope is complete so that those attachments can be used for things like user verification or as backup information before signing. For example, if the initial signer needs to verify their identity with an attachment (i.e., a scan of a driver's license), or if the initial signer needs to supply information other signers need in order to determine whether or not they should sign, those attachments cannot be used as they can only be seen after the envelope is complete. It makes those attachments useless as they can’t be used during the signing process.