"Might be controlled from ones phone."
I can control my Squeezebox Touch device (which includes
digital volume) wirelessly from any mobile device including
phone or tablet on my home wifi network today.
The technology exists to control anything from a phone
today. All that is needed is a market.
I use a pre-amp mainly because I have analog source (phono
and tape) in addition to digital. It may sound better this
way as well. Never tried it without the (tube) pre-amp), so
don't know.
Even if direct does not sound sound as good as with pre-amp
in my case, I see no reason why a separate pre-amp is
required for better sound. It may or may not be better
case by case it seems to me.