While I agree that it should be an option, you are better off converting everything to PCM anyway.
You can't perform DSP if you are bitstreaming DSD, which means losing things like the Volume Leveling feature that keeps playback volume consistent across all albums, the ability to use DSP like the room correction / convolution features (and more), and you have to trust that your DAC is doing a good job with playback.
For example: the DSD spec calls for playback to have a 6dB boost applied.
In my library, that would push 65% of the tracks into clipping if the DAC does not have additional internal headroom. My DAC has 3dB of headroom, which would still mean that 5% of the tracks would be pushed to clipping.
By default, Media Center does not apply that 6dB boost to DSD to PCM conversions, and if you have run audio analysis and use the Volume Leveling feature, it will prevent all clipping.
The DSD spec also calls for a soft low-pass filter at 50kHz, while that does nothing but allow considerable amounts of spurious noise to be sent to the amplifier.
Media Center's default filter cuts off at 24kHz instead, filtering out all of that junk ultrasonic noise, which should reduce distortion (you can also select 30kHz or 50kHz filters if desired).
You could use Bitstreaming if the DAC can handle the format:
https://wiki.jriver.com/index.php/Audio_Connection_Type
The issue is that bitstreaming in Media Center DSD is all-or-nothing.
My DAC will bitstream DSD64, but it results in me being unable to play DSD128 tracks.
Other DACs may handle up to DSD128 so DSD256 tracks will not play etc.
Roon's settings appear to use "up to DSD64/128/256" rather than "DSD Bitstreaming On/Off".