My experience with outboard DACs goes back to the mid to late ’90s so I don’t know if it would be applicable to the digital of today, but back then I did find that adding digital separates between my $600 Carver CDP and my preamp improved the presentation.
A few years ago I decided it was time to upgrade my ancient front end, so I bought Marantz SA10 because I wanted to do the SACD experience and I also wanted to get away from separate boxes and the cabling that goes with them.