This is not true. First everybody gets more sleep not less. After the first month or two if you are nursing you can just hook up and go back to sleep.

The risk of SIDS is lower with co-sleeping, and the risk of suffocation or those other horror stories is minuscule. And on top of that they typically only happen with parents who are morbidly obese or on medication (not just illegal drugs, but things like cold medication).

So the prudent thing is not to cosleep it if you took anything, but otherwise it's better.