Hi there,
Spotify webplayer requires Flash to play audio and to decode the tracks.
You might want to support this idea here:
https://community.spotify.com/t5/Spotify-Ideas/Integrate-HTML5-with-play-spotify-com/idi-p/596108
They use flash because they want DRM. As far as I know all on-demand services do. I know for sure Google Play, Rhapsody, and Slacker all require Flash and last I heard so did Deezer and Tidal.
Hey there you, Yeah, you! 😁 Welcome - we're glad you joined the Spotify Community! While you here, let's have a fun game…