Well, this actually isn't TOO bad.
It depends on duration. If it requires the traitor to keep the item out and activated in order for the blinding effect to continue, then you are right. If it blinds multiple people for an hour and a half(Exaggeration of course) then no, this is terrible.
The major problem I see with it is
or preparing to kill a dangerous target.
Which is part of the reason such items are not currently in the game now. If I recall correctly BKU doesn't like "Cheap" kills, defined as any kill in which a person can do nothing to stop it. In fact that was the whole reason for the knife change not long ago.