My best guess is that serger thread will not hold up well over time. I attended a Jamie Wallen workshop where he talked about visiting museums. Many have vintage quilts in storage that they are not able to put on display because the cotton quilting thread has dry-rotted over time. This is one reason he prefers to use polyester thread for his quilts (in his case, Isacord). Personally, I would not want any of my work quilted with serger thread.