Why it is essential to ride a very light bike

In contrast to common believe, it is not only better to ride a light bike if you move up hills. No, also in case of mechanical problems, for example a broken chain, it is much better to own a very light bike. You can do things with a 7 - 8 kg heavy bikes you could only dream of doing with your 20 kg electric-assisted shopping bikes. Also you do not need special training for your upper torso muscles.
David Millar demonstrated the advantages of a light bike at this years Giro d'Italia in a most memorable way. Of course less good-willing observers might suspect that he is on dope again. FORZA DAVID MILLAR !
[Please also turn on the Italian commentary full volume1]