I *used* to sleep with a Glock 21 under my pillow, unchambered for "safety". I did this for years, and years. Then I read a story about a man who shot his wife in the head on accident in his sleep, and went to prison. That man slept with a gun under his pillow, too.
It's an individual choice and I'm not going to fault someone for doing it, everyone has a right to do what they want. Just be aware there might be unexpected repercussions for every choice you make.
Thinking back to nightmare/dreams I had where I was pulling the trigger and couldn't shoot the bad guy (we had a thread on this recently here on THR), gave me the chills.. because it's QUITE possible while having those dreams, I was pulling the trigger of my Glock in my sleep. Without a round in the chamber, the trigger don't "work".
I agree about positioning, too. Tossing and turning I often found the gun on the floor between the headboard and wall.
Keeping it on the nightstand guarantees that when I reach for it, it's there, in the same place, every time. Handgun is close and convenient, but really only meant to get me those few steps to a much better option.
This is a great example of why one should pay more than just a tip of the hat to perimeter security, and put some actual serious thought in to it.