Yeah that one bothers me... The most demanding MP3s are what... 320kbps? That's 3.3GB per day. That is not really a hard demand on bandwidth at all. 100GB/month. And that's the max bitrate MP3 does... Most services are probably doing 128kbps...

Spotify has an Audio quality table on their site... https://support.spotify.com/us/article/audio-quality/

Low = 24kbps, 0.2471923828 GB/day
Normal = 96 kbps, 0.9887695313 GB/day
High = 160 kbps, 1.6479492188 GB/day
Very High = 320 Kbps, 3.2958984375 GB/day

These are very reasonable and easy numbers to obtain on just about any internet connection. The only way this is an "issue" is if you're running like a couple hundred streams at once.