Sure. But even if this would be a full tradeoff between product performance and energy use (which it really isn't, you can typically eliminate a lot of power co

Sure. But even if this would be a full tradeoff between product performance and energy use (which it really isn't, you can typically eliminate a lot of power consumption without impacting performance at all in domestic appliances), than that would be already an improvement: Without any energy labeling, the manufacturer has basically no incentive to provide any comparable information on energy use (especially if his device is subpar at it), and it's impossible for consumers to make informed decisions when buying (and very easy for extremely wasteful trash-products to get sold). It also would be very appealing to just waste a ton of electricity for marginally better performance, because wasted electricity costs the device manufacturer nothing.