To really get a feel of what difference weight makes then ride two bikes at the extremes and you will find the answer. Comparing an 8kg bike to a 8.7kg bike is not going to do that.
Ride a 6.5kg bike and then a 16kg bike and see which feels nicer to ride, handle, accelerate, go up a hill etc,. (obviously there will be many other factors but the weight will be the main one)
To really get a feel of what difference weight makes then ride two bikes at the extremes and you will find the answer. Comparing an 8kg bike to a 8.7kg bike is not going to do that.
Ride a 6.5kg bike and then a 16kg bike and see which feels nicer to ride, handle, accelerate, go up a hill etc,. (obviously there will be many other factors but the weight will be the main one)