It would be pretty nice to increase my waking hours by 50%! However I have a suspicion that if we didn't need to sleep we never would because the working day would go from 9-5 to 9-9 or more and who wants to sleep their personal time away?
Assuming you never felt tired there'd be no purpose to it - I'd also point out that if you don't feel tired or get to the point where you need a bit of sleep, there'd be nothing compelling you to do so.
Think about it. There are two reasons I go to bed, one is that I'm tired and the second is if I know I have to be up in the morning (or whenever) and if I don't sleep I'll be tired then (or unproductive etc) and so try to force myself to sleep.
If you suddenly removed those two issues from my life, nothing would compel me to sleep. I just wouldn't because it wouldn't cross my mind.
And then you could also consider, if you didn't need to sleep and didn't feel tired - would you be able to sleep?