If you are worried about snapping your bike, this might be useful information. If you want to compare how you stack up against others, I think you want to be checking watts per kilo. Even if you go to a gym that has a stationary bike to get an idea of what you can do, and then compare that to your body weight, that will give you a better idea of how you stack up. If you are anything to write home about, whether one's bike is 7 kilos or 10, should not make that much of a difference.
Adding excess weight to things that go up (and down) require more work effort. I've been riding with extra 2kg on each my legs as part of some muscle strength training. Believe me, the weight there feels a whole lot heavier than carrying 4kg of extra 'bike' ! Weight of a bike matters more when you can't reduce the weight from your body without causing muscle loss that affects power. At then end of the day its w/kg count for climbing and just pure watts for TT and general riding. If you're climbing, even 200gr difference will mean 'something' at the end of a 20km 10% grade.