You asked a question. I answered. Why should I assume you know?
But what's your point? That isn't the point of this ram... Don't think it outputs much heat? After playing games all day or rendering or really anything that uses a lot, touch it. Tell me if it burns a little, I've even touched the die itself, hot as hell. Either way, the point of this is obviously not for speed.
They have two clear steps from this ram that is actually very smart.
They are the first afaik to bring low voltage DDR4. This means they can bring it to mobile and probably still be running faster memory than most laptops even with 2666. Lower temps and power consumption? What was pretty darn good and is now exceptionally great.
Secondly, they are binning these chips. If they can continue they could probably get to 3000mhz rather soon. DDR4 overtime will improve and voltages will get lower. It happened with DDR3 and most kits ended up running the LV tag towards the end of life, so why not get ahead of the curve?? And for say Ryzen where most chips seem to not currently get over 3000, 2666 isn't going to make much of a difference.
In addition to the binning, you have more headroom for OC'ing. Starting at a lesser voltage you can still stay within "recommended tolerances" and more than likely get pretty far for those users who have say bad CPU memory controllers and need the voltage bump.