I'm not sure how to feel about the mechanic, but it would be the ONLY way to be faithful to the tabletop without a confirmation prompt at literally every action taken.
Sorry about missing your post on the issue, following mega-threads isnâ€™t easy.
I can see an alternative to a time-based system for Cutting Words that doesnâ€™t prompt incessantly. If the prompt appears only when the d6 matters, there would be far fewer (if any) unnecessary interruptions.
The pop-up would only appear if the enemyâ€™s d20 roll plus modifiers beat the target by 5 or less. If the roll either failed or succeeded by 6 or more, subtracting a d6 wouldnâ€™t matter so no pop-up would even appear.
Since this is a buff to Cutting Words, I recommend not telling players what the actual roll is at this stage, just that CW could work. (The game already reveals all ACs and DCs anyway, so showing the roll the way 5e does it would let players calculate exact odds, which 5e doesnâ€™t allow without some work.)
This has the added bonus of not requiring a special UI for Cutting Wordâ€™s prompt, since the promptâ€™s very appearance on screen would be all the information a player needs as to the enemyâ€™s roll: itâ€™s within CW range.
I hope a similar system gets implemented for Bardic Inspiration, though it wouldnâ€™t work for Portent. But if I understand mrfuji correctly, Portent isnâ€™t in the playerâ€™s handbook, which neatly solves any technical issue by not being implemented in the first place.