I am a little confused, do you mean that one should lose the kiu sao for forms practice or for application?
For forms practice, no I don't think so. I does help train the arms and does specific stuff to the nervous system that is important to developing ging.
For fighting I would never use it in street fight again. While it did stop the fight quick I nearly broke my damn finger in the process. Believe me eye pokes are fight stoppers, but use a cranes beak instead.
Now a claw IS very usefull in a street fight or a MMA fight. I love using them against my MMA buddies when we spar. The always complian because it is usually followed by me using a strong grip on whatever I hit. hehehe. BTW- doesn't work so well on a good muy thai fight though!