What was the purpose of giving Artificer’s something that’s going to be exactly extra attack 99.9% of the time (since they can make their own magic weapon) instead of just giving them extra attack? Were you worried Artificer’s would exploit regular Extra Attack? Playtesting. We're experimenting with a class-favored version of Extra Attack, which ties into the class's theme: magic through objects. Playtest feedback and our own tinkering will determine whether the feature survives in its current form.
— Jeremy Crawford (@JeremyECrawford) March 5, 2019
I imagine almost all of the feedback will be some variation of:
“Why does this exist? It’s more awkward and complicated than it needs to be, it literally adds nothing of value to the player experience, and it will occasionally result in unusual edge cases that 1) will require more bookkeeping / better player memory and 2) will frustrate players with a senseless feeling limitation.