Surely the question relating to Einstein and Chopin is rather irrelevant as their worth is judged on things they've actually achieved, not the potential that their qualifications display.
And yes, there is a difference in worth to degrees. I feel it's because the world has more need for people educated in medicine/engineering/etc than it does say... fine art. Also i would argue that getting a degree in medicine takes more time, energy and intelligence than a degree in the aforementioned 'fine art' would. That's not to say people who take these 'lesser degrees' aren't as intelligent, but they have chosen a path that requires less use of intelligence imo.