Set up reminders
In accordance with the "inbox zero" philosophy, Inbox by Gmail gives the user two main sorting options for any mail: either "Mark as done" or "Set up reminder". "Mask as done" is basically the same thing as "Archive" in classic Gmail and Geary. "Set up reminder" allows the user to set a date in the future where its mail will reappear into its inbox. So, in Inbox, your mail is either in the inbox (= to do now), set to an ulterior date (= to do later), or marked as done.
How would you like it to work?
Currently, Geary features two "sorting" buttons on the right side of the top bar: "Archive" and "Delete", in addition to a "Star" button and a menu button at the top right corner of the email itself. Inbox by Gmail displays four "sorting" buttons (plus a menu button): "Pin", "Set reminder", "Delete" and "Mark as done". The mobile version is simpler: swipe the mail to the left to "set reminder", swipe right to "mark as done".
I understand that altering Geary's layout to better suit suck a workflow may not be consistent with the design goals of the project, so this is just a suggestion, based on my own experience of being used to Inbox (and Inbox Zero) and wanting to move out of the Google ecosystem. Maybe there are other FOSS mail clients that are better fit for my intended usage?
Relevant links, screenshots, etc