DJM-900NXS2 as permanent mixer for PC - good or bad?

I kind of have my DJM-900NXS2 as a permanent mixer setup for my PC, and this also works as my "go-to setup" when I'm rented out as a DJ.

Connections:

• x2 Pioneer XDJ-1000
• x2 Numark players
• One of the Numark channels also shares its output with my USB soundcard so that I get sound from my PC.
• x2 XLR connected to the master output for my 2 studio speakers
• RCA master output connection from my subwoofer (for a 5.1 surround system, which I guess makes stereo because of this). This is so that I can turn on this sound system when the computer is off and doesn't depend on the USB soundcard (which has all the 5.1 surround connections).

Anyway, in order for my whole sound system to get sound, I must turn on the mixer, which means that the mixer will be running for as long as I want sound from my computer. I also use it in order to DJ in my home, either with USB play or MIDI with VirtualDJ on the computer, which means it's always connected to the PC.

My question is, though, if it is healthy for the mixer to be used like this? Or should I instead use a smaller/cheaper mixer for this purpose? Feels like I'm wasting hours on such an expensive thing when I'm not DJ:ing for real, instead using it to get sound from my PC. I also have an external Focusrite soundcard that has the required connections for my sound system, but I'd like to be able to equalize when I play music (in any way), especially the lows, since I live in an appartment and wouldn't like to make too much noise.