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

"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.  

Relatively new to the site but it seems like there are two threads rolled into one here.  With regard to what I’d like to call the “highest of the high end” those involved in it, IMHO, are correct.  Separate systems for HT and two channel audio are a given but there are many of us who enjoy our music reproduced with quality sound who are happy (at least temporarily) with “higher” end sound.  So if one has only one space for both music and movies the HT Bypass option is an acceptable solution. In looking to upgrade to separates with tube preamplification and a solid state amp I came across the Rogue Audio RP-1 which looks like it will operate in bypass mode when the preamp is off thus expanding tube life.  Am I correct?  
Also, I’ve listened to $100k and $500k system so I understand what the goal is but it’s just not my goal.