You don't have just use them on beds. They can be wallhangings, table covers, playmats, little ones can be used as table runners and table mats. You can make quilted bags, clothes and boxes. The pattens and techniques are very versatile.
It always troubled me that my duvet covers weren't exactly to my liking, and DP broguht a duvet cover to the relationship that was blue and just didn't go in my bedroom, so the quilt is a godsend becasue it goes over the top of everything else and always looks nice. If it gets too warm to sleep with it we just fling it off.
Very useful for snuggling up on the sofa with too.
It is best to pre wash the fabric and the wadding before you sew it together to avoid it shrinking at different rates and puckering up. On the other hand some people like the home spun slightly puckered look so it isn't necssary. So long as you bear the potential for shrinking in mind you can wash it as much as you like.