One way or another, a system needs volume control and source-switching (assuming it has more than one source). If you have only one source, and it's digital, you could get away with software volume control only. In my limited experience with it, software volume control seems to compromise SQ compared to a good hardware implementation.
At any rate, in between a computer that runs DSP (like HQ Player) and a power amp, there generally needs to be a box with USB/other input (at least) and loudspeaker outputs. How is it a hindrance if that box supports source switching, volume control, IR remote, etc.? Unless you just want to connect powered speakers (or headphones) directly to the computer. But then you need a keyboard, display, mouse/trackpad to control the computer (instead of connecting a "headless" computer to a component audio system). Seems like more of a hindrance than a preamp.
At any rate, in between a computer that runs DSP (like HQ Player) and a power amp, there generally needs to be a box with USB/other input (at least) and loudspeaker outputs. How is it a hindrance if that box supports source switching, volume control, IR remote, etc.? Unless you just want to connect powered speakers (or headphones) directly to the computer. But then you need a keyboard, display, mouse/trackpad to control the computer (instead of connecting a "headless" computer to a component audio system). Seems like more of a hindrance than a preamp.