Integrated: Reduced Space; Remote Volume; Reduced Interconnects; Reduced Cost.
Remote Volume (modern preamp or modern integrated) effects top shelf space requirements. I used both SS and Tube Amps (Stereo or Mono) for many years on lower shelves before I wanted remote volume. Remote volume requires at least desk high shelf height (my top shelf) for remote beam use.
Reduced Space:
My 13’ wide room, large speakers away from corners, leaves only 88” linear shelf for active components. R2R on top reduces that to 88”. TT reduces it to 48” = only two short stacks of equipment, 4 of which use remotes.
1 digital stack, 3 remote devices:
Single CD, Multiple CD, Chase Remote Line Controller (my separate digital integrated, I use primarily for remote balance of CD’s, especially compilations of separate recording sessions). I found, a very slight balance tweak can make a surprising amount of difference to many CD tracks. It goes to my Integrated Tube Amp's AUX input.
1 tube stack, 1 remote.
Tube preference, heat from tubes effects top shelf space requirements.
I just designed and built a ventilated enclosure with floating solid glass top so I can stack my modern Integrated Tube Amp Cayin A88T over my old McIntosh Tube FM Tuner/Preamp, mx110z. (they only made 6 tube tuner/preamps, 'separates' took over soon after). The McIntosh incorporating FM Tuner, Phono EQ, Tape EQ reduces the need for those separates. Note: my choices of modern tube amp is limited to units with 16 ohm taps. I expected my modern Carver FM Tuner to beat the mx110z FM tuner, but happily the McIntosh FM is equally awesome. A dedicated FM antenna is needed for these older tuners. I listen to one station, WBGO Jazz, so the Carver was on a lower shelf.
As it has no remote control, I could put the McIntosh Tube Tuner/Preamp 1 shelf down, as I did with prior tube receivers, but that is a compromise I never liked.