The rotary blade sharpener mentioned above IS a waste.
I, too, have never gotten the chalk pounce to work right.....or at least, not work the way I want.
I love the bobbin winder --- I use it on the Longarm. That machines winds its bobbins but the needle goes up and down. This is BAD when you're in the middle of a quilt.
I LOVE the purple "thang"....it's been a BIG help.