The app passes the Qobuz music via your streamer to your audio system. The app is controlled by your iPad separately and has no effect on the music stream or it's quality.
And, Roon playing Qobuz sounds great. I use their Nucleus streamer and also tune Qobuz vis the internal streamer Mosaic in my dCS Bartok DAC. I can hear no difference on a six figure audio system. If Roon does not sound right on your system, you may have something to better optimize with your internet hookup.