Well, it is in a way. A 30lbs beach cruiser is a lot harder to ride up a hill than a 14lb top-end pro racing bike. The problem is that expensive micro adjustments are probably not worth the cost in terms of actual performance gains. Making your bike 300g lighter will probably have no effect on your ride. That 14lb bike is over 6,000g. 300g represents about a .5% weight reduction. Even less on a 20lb bike.