Sleep debt is not a good thing. You may not realize it, but it leads to exhaustion and impaired judgment. I do it several, but I usually find time at the end of the week to have some good rest. Extended sleep deprivation will harm you greatly. But sometimes its just unavoidable.
It is possible, especially when i have tight deadlines. But it is not a good thing. It will lower your productivity. You should not do it more often.
absolutely, i can stay up all night playing games i usually don't sleep too much, maybe about 5 - 6 hours per day. it is crazy, i know