Silly thing is, I have a pretty good idea of what those "Singer" sewing machine accessories are used for, thanks to a little commercial sewing training.
Old Treadle Sewing machines, have proven to be some of the worst investments, as far as value as an antique, goes. Expensive as hells, in their day, but the owners took decent care of them, and now there are far more than the market really can support, so they sell cheap.
I met a guy that made a pretty good living custom building stuff for the 'Whips and Chains' set. Not who I want to hang with, but they are willing to pay a lot for their toys and accessories!