I really don't understand what you're saying here. I hope you're not still mad about that one joke.
I missed it. Life's too short to get mad with people on Internet forums.
Perhaps it does what you say, but at the end of the day, it's also this:
A player just like foobar or VLC. Maybe there's an app with a similar name or something? Anyway, in this app, I found a setting offering to enable USB speakers. This COULD mean that when enabled, it sends digital info over USB.
I'm not saying it is, because today at noon (my time) I'm yet to buy the test USB DAC. I'll let everyone know and might make a short report. Perhaps I'll be able to help someone or at least give him an idea of what might help.
I was explaining what this software does in its back-end. What you are showing above is the web-based
front-end of the app. Effectively, the NAS management software is allowing you to see
when directly logged into it's web-based management capability, what is going on below the user stack. I also have the same GUI above when logged in to the management console and have had ever since I installed my Synology almost a decade ago. Mine does not have a USB option (current v7) and I don't recall ever seeing it. But that might be because my Synology is old.
Via wired or wireless packet network I can get to my audio files via two principle ways - (1) via CIFS/SMB mounting the
generic file Network-Attached Store (NAS) which requires nothing fancy at the NAS end*; and 2) via DLNA/UPNP which is delivered by the Synology Media Server (which is not a generic NAS-type service but an add-on that runs in Synology's host-services environment). Also, the inbuilt indexing services ensures that the Audio and Media Server content lists are up-to-date. My streamer works using the (1) CIFS facility and I can also listen on my smartphone via DLNA using (2) and the Synology DS Audio app for Android.
* I have experience in procuring and analysing data-centre-scale file storage (effectively NAS) and block storage. There are things that a generic NAS
must do, and running audio drivers on a USB interface is not one of them. But some domestic products may do so as an added function of their host - this is one of those YMMV things.
What others have said makes a lot of sense: if you roll your own NAS using an old PC/Laptop etc or a Pi, these are rich hosts which can have all sorts of extra benefits. For a direct NAS to DAC with the least number of connectors, there's a lot to be said for this approach rather than an off-the-shelf NAS device where they may not see enough profit from adding in what is quite a niche requirement.