Cutting Words vs Attack Rolls

 The College of Lore Bard's ability Cutting Words allows a Bard to reduce an attack roll with one inspiration die roll.  That's a d6 to d12 reduction in an attack roll that can easily be the difference between a hit and a miss.  The rules on it are rather clear and it has been clairfied with a Sage Advice but it seems to lead to an undesirable in play result.


 Following are the rule snippets that control this ability.

College of Lore from PHB

When a creature that you can see within 60 feet of you makes an attack roll, an ability check, or a damage roll, you can use your reaction to expend one of your uses of Bardic Inspiration, rolling a Bardic Inspiration die and subtracting the number rolled from the creature’s roll. You can choose to use this feature after the creature makes its roll, but before the DM determines whether the attack roll or ability check succeeds or fails, or before the creature deals its damage. The creature is immune if it can’t hear you or if it’s immune to being charmed.

Sage Advice 

Is the intent that a bard gets to know the number rolled on an attack roll or ability check before using Cutting Words, or should they always guess?

If used on a damage roll, does Cutting Words apply to any kind of damage roll including an auto-hit spell like magic missile ? You can wait to use Cutting Words after the roll, but you must commit to doing so before you know for sure whether the total of the roll or check is a success or a failure. You can use Cutting Words to reduce the damage from any effect that calls for a damage roll (including magic missile) even if the damage roll is not preceded by an attack roll.

Notice that they allow the Bard to wait for the roll but not know the total of the roll before deciding. Presumably the Bard can be told the result of the roll without the creatures modifiers before deciding to use cutting words or not.

This means the DM needs to announce each and ever unmodified roll and allow time for the Bard's player to cut the roll or to allow it to stand whenever the Bard could choose to use Cutting Words.  Doing this would be a big slow down in play -- Undesirable. 

It also means that as a battle progresses the players can likely figure out what the attack bonus of the creature is.  Not real important, but this seems like -- not a good thing.

The benefit of deciding to use Cutting Words before knowing if the roll is good enough to hit is a bit of game play, an opportunity to guess the right course.  That is probably a good thing, but with the other two downsides, is it worth it?  If the Bard player knows that an attack is a hit by anything more than one they still could use the Cutting Words ability and fail to block the attack.

I just don't see this as a useful thing, the delay is far worse than the benefit is good, so:

Cutting Words: Cutting words may be used after the total of an attack roll is announced.