Yes. UAPP is the best $ I have EVER spent on an app. If you are paying the cost of Tidal lossless, then you care about audio quality... why would you not pay $5 to have access to UAPP for the rest of your life?
Without UAPP, youre generally going to be using your phone's DAC and only the amp part of your external device. In the best case, you will output an upsampled digital stream to your external DAC.
Interesting note though... I read in Tidals FAQ a while back (I think thats where it was) that Tidal MQA requires bitperfect playback... but that doesnt make sense to me, since Tidal does not utilize bit perfect on my device, yet I still am notified via my MQA enabled device that it is playing MQA content?? Interesting, and confusing... oh yeah, it's audio stuff... it's all confusing