Getting through Promotional Emails
Even though there is a 'skip promotions' feature, I find it best not to use “skip promotions” and instead double tap when they appear so they are cleaned out of my inbox.
I also use “ignore sender”, but again that doesn’t mark as done. Other people might not be after an inbox clean but more an email scan so it would be useful for their case.
If you do switch on "mark as read when speaking" (under Account Settings), it will 'mark as read' every email as it goes past including promotional emails that it skips.
See also "It is skipping too much or not enough"