We have a set of Filters on the top picker where All = Incoming + Snoozed + Done.
Marking as done allows you not to see that mail (it still exists) when using Incoming filter.
Read / Unread is involuntary and provides the state of the mail.
Note: You will see both Read and Unread using Incoming. You have Unread filter and you can use it to see only Unread mail.