Sorting is the first step, not the last one
Filing an email correctly saves you opening it. It does not write the reply the message asked for, create the task it implied, or put the meeting in your calendar. CevroFlow's categorisation is the same first step, and then the same single read produces the draft, the task and the meeting details. The measure worth applying is not how much of your inbox got filed, but how much of the work in it got done.
