Based on the recent news from Spotify, it seems like a licensing issue.
Based on this alone, my guess is 2 things will be cleared in 1 day:
1. Spotify HiFi
2. Tidal Desktop Connect control through mobile devices
Why? Because Spotify already have Connect control for desktop, while Tidal already has hifi, but not Desktop Connect. It looks like with "Connect", there are some temporary file downloads that happen and I think when CD resolution files are downloaded, it becomes an issue with the content providers. Piracy most likely is the concern, because there are third party tools (I believe) that have capability to convert Tidal/Spotify songs to FLACs, etc.