To generalise, the difference is in verification time / amortised time. If finding the real answer would take me an hour, but I can check a proposed answer in 5

To generalise, the difference is in verification time / amortised time. If finding the real answer would take me an hour, but I can check a proposed answer in 5sec, I'm going to try at least 20 of the 90% answers before starting the work myself. On the other extreme, if verification would require finding the same original sources that contain the actual answer, then there's no point trying even the 99.9% correct answers.