HT Bypass Vs Input selection Integrated Amp

Hi Folks, i am looking to supplement my HT receiver with network streamer +DAC. Today I have the marantz receiver (SR 5015) running preamp outputs to my 2  channel Parasound power amp, which power L/R. I also do however listen to a lot of stereo music and want to add a network streamer (Arylic or Node or Wim pro), and an outboard DAC (geshelli labs j2 or Topping E30). I have been looking into solutions like the Schit Sys which seems to be cheapest, quality means to switch between two analog inputs.

I'm also now learning of HT Bypass, which some integrated amps support. That said, why can't I just get a regular integrated amp and toggle between input 1 vs 2? What is the difference between one vs the other? Thank you!