[paxys]

Bandwidth costs for text messages, maybe, but how much data is that really compared to images, audio, video or even just the app's JS bundle?

[bri3d]

Presumably that's all CDNed and therefore a lot cheaper to serve.

[bguebert]

Probably not for live shared audio/video

[toast0]

The bandwidth probably doesn't really matter, but a 2MB must have blob vs a 300kB must have blob at the start of a connection is a big difference.

The start of a tcp connection is limited by round trip times more than bandwidth. Especially for mobile, optimizing to reduce the number of round trips required is pretty handy.