Oh no the old rotational weight chestnut is rearing its head, some of you guys need to stop reading internet forums.
You really have to wake up to the fact that when you save weight on a bike of a few hundred grams its make sod all difference, regardless of the weight being on the wheels or grips or tyres etc.
Looks at the weight of the fatty who is riding the bike, even at 70kgs the rider is a much bigger influence on the bike than anything. By a factor of 350 when talking about these tubes.
How many on here could still lose at least 5kgs. Do that before you start spending £40 on a tube just to save weight.
Most sensible rider buy gear on its function and durability not weight.