I LOVE the fusible batting from Hobbs - although the last couple that I bought didn't seem to stick as well as the first few that I bought. I was going to ask Hobbs about that - if they've changed their formula or something.
If you have a quilt top that won't behave and lie flat, the fusible batting can help you beat it into submission.
There have been a few quilt tops that I've bought on eBay that would have done me in if I hadn't been able to fuse them to the batt. They were poorly pieced, not pressed during assembly, not square, not flat, not smooth... yeesh!
Fusing them to the batt helped me get them smooth enough to quilt, then I could wash them and the wonky spots were either no longer visible or not as obvious.
After you wash the quilt, it is as soft and drapey as any other quilt.
It is no fun crawling around on the floor to iron the top to the batt and then turn the whole thing over and iron the back to the batt. I save basting of any kind of bed quilt for the days when I'm going to put up my 8-foot square "basting table." (made of sheets of MDF & 2x4's)