I have about 17 sewing machines, most are vintage. The ones that are mechanical and all metal parts are often wonderful. Many have only straight stich but are great for piecing or sometiems quilting. The value often varies from $35 to in the hundreds for Feather Weights. Pitty you gave away the treadle. And Yes, I definitely use them and often prefer to use them over my newer wonderful Janome 6500. Only some can do more fancy stitches. some will have stitches build in or you have to use cams. As for button holes, I think many need several steps if they even do button holes. Some only do straight stich and there is no reverse, and some only do straight stitch, zig zag and reverse.
Singer 401
[ATTACH=CONFIG]252039[/ATTACH]
Singer 201
[ATTACH=CONFIG]252040[/ATTACH]
Feather Weight
[ATTACH=CONFIG]252041[/ATTACH]
Treadle
[ATTACH=CONFIG]252042[/ATTACH]
Singer 301
[ATTACH=CONFIG]252043[/ATTACH]