There are different kinds of beds which can be found in some of the huts and tents:
- normal beds
- camp beds
They act as one of the two save mechanisms (the other being lamps). To use them leftclick at the "Zzz" icon which appears if you're beside a bed.
Sleeping in a bed helps against fever. It works basically like taking Basic medicine or Extra-strength medicine, so if you're fresh out of pills and no time for cooking some up, why not take a nap!
During sleep passes some time (around 6 or so in-game hours), even though nighttime does not stop the creature from spawning some prefer to travel at daytime. So it's a good way to skip the night hours.
A typical camp bed inside a tent