The question that started this thread was whether the bike is WORTH saving. That indicates monetary value, not emotional value. Emotional value is easy, or if you prefer, about the passion. There may be no limit. There are a number of bikes I would put into this class, but this isn't it. Monetary value may sometimes have something to do with being collectable, but this isn't one of those either.
I commented before that it would cost around $80 to fix it up and John replied:
Yes, but it will run circles around any new bike costing twice or thrice that $80 investment, which still makes it economically defensible.
Twice the amount, maybe, three times, not a prayer.
This is a Schwinn World, one step above the Caliente, on a good year it sold for $190. I has pressed steel hubs famous for separating at the press, this mostly happened when the rear triangle (soft grade hi-ten steel) got bent (almost as often as stamped stay Murrays--remember those?) and caused the rear axle to brake, because the drop outs no longer lined up and the frame with a heavy rider didn't have the strength to hold the hub together. It never used better than a ty-36 der set, was indexed on the right hand at last production--and this bike isn't one of those either. I'm not even going to get started on the steel rims, side pull brakes (that would scrub some speed before impact but would never skid a wheel--as required by law) or the "safety levers" on the brake levers.
Now if you are asking if this is a good bike to learn solid principles on bearing adjustments, installing tires, cable routing, wheel truing, derailleur adjustments etc. then the question is retorical, the bike is free, you can destroy with immunity.
Am I passionate? Not about 20 year old death traps.