Fatal Familial Insomnia is an incredibly rare prion disease that causes widespread neurological destruction. It's not remotely a normal brain that has chosen not to sleep. It's such a highly non-trivial deviation of the brain that we've only identified a few dozen families in the entire planet that suffer from it. At this point, quite a lot of things have already gone wrong in your brain.

There is quite literally no prion disease that isn't fatal.

Sleep does a lot of very important things that we probably wouldn't live long without, but it really is unclear to what extent sleep is necessary for them. If we had enough knowledge, could we trigger all the things sleep does without invoking sleep itself ? Perhaps sleep is just a very convenient mechanism.