If I could get one for cheep I'd put it in a treadle and find out. I suspect it would work OK. I know what the insides look like as the Janomes and Singers are made very similar on the cheaper models. You can see the family resemblance when you look at them.
Since you'd be turning it by a treadle it's not gonna be turning as fast as an electric version so the plastic insides should last a while.
Supposedly the Amish use them so they must be fairly well made. At least you'd think so.
Joe