I use quilts as table cloths all the time. I don't have young children and that does make a difference. If we are going to have something that is especially staining like spaghetti then I will either use something else or place mats over top the quilt. When they get dirty I wash them and treat any spots if necessary. A lot depends on the fabric used too. If it is a busy fabric then spots don't show on it so after washing if there's a smudge or two it goes unnoticed.
I enjoy quilting for the process of quilting. How many show quilts and wall hangings can one have so I make things that are used everyday not so much for the end product (although I do enjoy the end product too) but rather the fun of making it and learning something new. Rarely do I repeat patterns.