Dragging from Outlook is also an improvement, but a different one.
Email importing allows you to setup automated process to a much greater extent (I use for example Outlook quick-actions to automate several steps, Taskclone to import Evernote-tasks and more).
Dragging from Outlook adds the advantage of the email-id being copied so you can open it directly.
I see these as complementing features, not competing ones. And email import is essential in order for your todo-app not to live in its own world.