What is the relevance of this test? One cap and one nut weigh 1.5g together. Adding that to a balanced wheel makes it still far more balanced than 99% of stock wheels out there.
When I hammer down my local climbs, I prefer my wheels to be balanced to remove one source of oscillation I can easily control. This does not mean that this is compulsory to do so in order to be safe, or that it can be specifically felt.
the point is if you’re balancing a wheel, it’s a pretty small aomount of weight. Look at your car wheels/tires. The combination of the wheel and tire on a car is ,20, pounds or more. The little lead balancing weights are a tiny fraction of that.
The nut and cap on your bike wheel are at least as large a percentage of the total wheel weight as the balancing weights on your car wheel.
if it actually made a difference, the cap and nut should be perceptible and they aren’t