You can use it anywhere you want as long as you consider the fabric qualities and potential problem areas...for example, if the product you make needs to be washed, how will the fabric react? In this case, I'd try washing a sample to see the result. Curtains and pillow covers usually need washing less than quilts and pillowcases. Regarding the instructions to handwash and lay flat to dry - I've had many fabrics that say that but in fact wash up nicely...but that's why you need to try a sample..and even try drying it if you normally use a dryer.
Also, most linen's require a larger seam allowance because they fray. Is there a way to take advantage of the fraying...like on a chenille item?