This was my rationale for going with a dedicated streamer and external DAC.
As someone coming from analog, I knew the sound of a DAC would be an important consideration for me. Specifically, I was seeking a DAC that sounded more natural (detailed but also not harsh in sound). Going to a separate streamer and DAC provided more flexibility in finding this as the companies producing DACs of most interest to me tended to produce standalone external DACs. (mostly DACs with an R2R design rather than a delta-sigma design). It was not easy to find a one-box solution that had a streamer interface that I liked with a DAC that would seem to fit my sound quality preferences.