Hi end tube preamps, it’s all about functionality!!

Integration of high end sound system with  tv-video equipment will negatively affect SQ.  Extra functionality futures calls for extra circuitry which add interference and lowering SQ.  Solution is to have two separate systems and even better solution is to have those systems in different rooms. 

I regard having separate volume controls for left and right channels as added functionality!

I have a system for music (my top priority) and a totally separate system for movies and sports in the same room. Been this way since the beginning and works great.  I would never have even tried to have one system do both. Too many compromises. Check it out.

"Circuit boards and all the processing and switching used in AVR integrated units is something most folks here will avoid at all costs. Less in the circuit is more for music audiophiles."

For that very reason, you might wonder why you want a dedicated preamp at all. If you need a separate DAC/streamer anyway, some of them apparently are starting to have very good volume control and input switching. A selling point of some of the best-measured preamps is that they add nothing to the sound signature. So, why bother? This is not a rhetorical question. I suppose excellent volume control is one reason, assuming there is a measurable difference between what you get in a high-end preamp and what you get in some of the best DACs/streamers (like the Mola Mola Tambaqui, maybe). 

Because it sounds better.