The difference between Qoboz stream vs purchased songs

going to try to get this back on track…

@gkelly there’s only one way to answer your question - purchase a song or an album and compare. There are few variables that can potentially influence the outcome. Hear it for yourself. 
My opinion, which is largely based on testing and comparing stored vs streaming, is the money would be better spent on a second streaming service (i.e. Tidal) that gives you access to some music that’s not available on Qobuz.

I compared purchased music on hdtracks vs the same album on qobuz using Roon. The hdtracks files are in fact slightly better. Not dramatically but they are better. 

Yea the only way to know is for you to compare.

The correct answer is: theoretically, with everything else the same, there is no difference when source content is the same. But there are always external factors that can come into play in unique ways case by case.