Another factor of the fabric quality/ suitability for quilting has to do with the size of the individual threads within the fabric. For example homespun has thicker threads so a lower thread count yet a thicker fabric. While batiste has very thin threads yet a higher thread count but still a sheer fabric.
Personally I go by feel and appearance when determining whether I want to use a particular fabric in a quilt. And that may differ from one quilt to another.