ArchaicArcane,
I'm not sure why really other than both of the ones I have were in need of a lot of TLC. By rescuing them I saved at least one of them from being parted out. And by having one that was functional I was able to compare it to the other one and get him fixed too.
About the only machine we don't have a mate for is my wife's Bernina Record 930. And she's keeping her eyes open for one of those too.
Joe