Either way is cool. Since you ask, here is my use case:
My actual use case was to use just the minimeters app during reviewing music to confirm the resonances I heard and also to confirm balance issues between highs/mids/lows. Then people can analyze/review music just playing via e.g. spotify without a DAW or getting the music into the DAW.
I can understand if implementing this for the app version has more effort or has other limitations. Is the problem due to plugin libraries already having EQ/filtering logic compared to the app version(I do not know, I just wonder about it)?
I totally understand the use-case. I have thought about adding that for a while and I would likely use it in my own music production workflow just as I used SPAN. However, implementing that system-wide would be quite a large undertaking on both macOS and Windows. I'm sure I could get a minimum viable product on macOS done in a reasonable amount of time since Apple seems to support something like that in macOS 14.2 and later, but tools like eqMac and SoundSource exist and are battle-tested to be low latency and performant. I may dive into that one day, but am avoiding the feature creep as I approach finalizing the v1.0 update. Implementing it with the server plug-in is trivial and already "done" for v1.0.