The intent is to have
the ultimate amount of control over the mix. Dead
Rooms and synthesized sources help create that
circumstance.
Or great sounding rooms with excellent natural reverb so you don't
have to apply any effects at all? Of course, not everyone has access
to one of those.
I'm lucky enough to have a studio next door to a large house with its
own ballroom - wooden floor and high ceiling. The guy who originally
built the studio put four balanced cables and a headphone return
under the lawn, so there's a wall box in the ballroom connected to a
loom in the studio.
Recently I recorded some vocal/acoustic guitar pieces - first we tried
the very dry vocal booth, then the ballroom. The recordings from the
ballroom sounded so good that we didn't bother trying to add
artificial reverb to the vocal booth takes.
This might not work for every kind of sound though, and the occupants
of the house wouldn't be too pleased if we had the drum kit in there
or electric guitars, playing late into the night as we usually do...
Cheers
Daniel