The whole system where all of these projects generally go towards some form of advertising where we convince people to buy things they don't really need is a far worse form of heat loss than this. Buying the latest shiny smartphone every year isn't just the heat loss of thousands of engineers making it slightly thinner, it's the actual loss of all the resources that went into last year's batch of smartphones that end…
Why would you say no to them?
Not the most important thing in the world? Sure. Something that millions of people want and are willing to spend 1% of their annual pay check? Yes.
Saying that it makes no sense constitutes a very destructive thinking. When you start thinking of what "makes" or "not makes" sense, you stop being empathetic. There's always a better, "more right", more proper thing to do and millions of people are just wasting their time on something they don't need. But aren't they human beings? Isn't having irrational wants rooted in the humanity itself?
Planned economy was dealing in the same maxims. "People need food". "People need shelter". Also tools and military equipment. Fashion clothes? Nah, screw that, useless. Beauty items? Shenanigans of capitalists. Some variety of food? We don't have resources for that.
We know how that ended up.