IMO there is an issue with the author's thought in the last paragraph. The advice is related to a test, and it stands good. You aren't asked to leave the tough questions unattended; rather you are asked to answer the easy ones first, then come back to the questions whose answer you didn't know immediately. This is time management. If you choose to do the opposite, attend the hard ones first, whose answer you might not even know, you are wasting your opportunity.
Real life is a bit different, here you aren't being asked to solve a test. The questions (or say tough situations ) you are presented with, you choose to either solve or skip them. And that defines you, builds you. The ones who are famous, they chose their question; what they wanted to do, they went after it.
We can't mix the two scenarios.