I've asked the same question and found this to be a pretty helpful explanation of the issues.
https://pitchfork.com/thepitch/1305-does-bluetooth-really-sound-worse/
https://pitchfork.com/thepitch/1305-does-bluetooth-really-sound-worse/
How Good Is Audio Quality When Using An Amp's Bluetooth Connection
My Rotel Integrated Amp has bluetooth capabilities. Was wondering if anyone has experience streaming music in a high end audio system using the bluetooth connection versus apple airport express or other devices? What is the quality of the audio signal when using bluetooth? I have heard that it is not good and that signal is compressed. Almost all of my audio files are AIFF.