While the segmenting feature is useful for some instances of exclusion/suppression, it certainly does not cover all possible use cases. Often, I am sending an email to a list with hundreds or thousands of email addresses, but I want to exclude everyone in a specific region, or that works for a group of specific companies. Other email service providers make this very easy to simply filter your list by those fields and exclude or include using the information in those specific fields. I don't need to create a permanent list of everyone in the state of New York, or who works from Company A, it's just that the information in this one time email send is not relevant to them. Creating a separate list or tag for a one time email send (or even 3-4 sends) is a waste of time.