while it will work, running a dac directly out of the usb port of the roon nucleus is not advised if sound quality is a priority (if it isn't, one must ask why pursue all this roon stuff anyways, right?)
there is a whole industry segment on upgraded switches, network isolation/filters, usb cleansers, optical conversion modules and so on - purpose of which is to isolate the computing/data management aspect of roon (which produces substantial electrical 'grunge') from the delivery of the streamed audio signal to the dac/renderer
pulling the audio signal straight out of the nucleus (or other core machine) is the noisiest, least desirable way of listening to a system using roon - same reason why non-roon based streaming from an everyday non-dedicated pc is ill advised
if for background, ambient, non critical music, then yes, fine, but it is the worst way to get good sound from a roon-based setup