Why is the audio playing restricted by default on my demopage?

What I want to archive: I am working on a proof of concept for visualising mp3 files in a simple manner.

What I am running into: If I visit the demopage https://poc-soundwave-ajmbesrkms.now.sh the soundfile is not playing (after interaction with the audio control bar! So no autoplay etc.). If I take a look into the browser settings there is always a domain restriction for playing audio files (no matter if chrome or safari).