I like the essential premise of Bed 42 from Manada which has a platform bed on one side (I’d put a bigger mattress on it) and a desk, out of sight, on the other. And having your work disappear from view can be essential to well-being.
Having spent years working in the same room I slept in (and the wonders of a Murphy Bed, I learned the hard way NOT separating work and sleep can lead to sleep disorders or, simply, a general lack of balance. Abundant research has shown that sleep really needs to be SLEEP in order to refresh the brain to be it’s truly creative self. It’s important to turn work — and doing — OFF for a portion of the day.