Hisense U8K has optical out volume control

[bigb76180]

I have a simple 2.0 system in my bedroom that consist of the Hisense U8K TV , apple TV 4k, wiim pro plus, and an aiyima A07 max attached to my speakers. Now I just use the optical output from the U8K TV to the wiim pro plus and while hooking it up I fully expected and intended to be using the wiim remote or wiim app for volume control. To my surprise I noticed that the hisense U8K still retained the ability to control the volume of the optical out signal. Since I had never come across a TV that would do this I hooked up and old soundbar to double check and it confirmed it. So much to my wife's happiness I'm able to set the wiim's volume all the way up and let the TV digitally control the volume which allows the use of just the apple TV remote only. It seems to have no discernable audio degradation that I can perceive but I'm no golden ear so take that for what's it worth. I also have the step down model the Hisense U7K I may see if it has the same ability as the U8K. This has me wondering has anyone else come across a TV with this ability to control optical out volume and also why don't more TVs do this ? In a world of soundbars and such it doesn't seem like it would be to hard to do like this U8K budget based TV has done. Thoughts ?