Email fields for Advertiser and Website entity are confusing.
1. In older versions this field was used e.g. for reposting purpose
2. After upgrade the email is still in e.g. Advertiser entity, however emails report are no longer sent using such email, they are only sent using user email which is linked to Advertiser account (if there is no directly linked user to Advertiser account, then email reports are not sent)
3. In 2.6 email field seems to be useless or at least confusing as in fact linked users emails are used.