The documentation about write access states:
The application responsible for creating content via the API may be indicated with a link to an app's Stack Apps post. The exact manner of display is subject to change at any time.
For example, API created comments current look like the following when hovered over:
Is this still accurate? I can't remember seeing this at all – maybe because it would affect comments from the mobile app too, causing too much noise? Or does "subject to change at any time" mean "we've disabled this for now and it's highly unlikely to come back"?
Anyway, it's probably better to remove it.