It is a joke that this isn't a feature yet.

Agreed... Any options to protect me from using my data would be preferred. Idea: a toggle for WiFi only (limit it just to streams, but still let me browse people /channels, etc), option to have a Warning message/banner if I am running on data/cell, an option to auto downgrade to low quality video when on cell (to use less data) .

Any combination of these would be awesome and would draw my attention as a user to the fact that I am not on WiFi.

Same here..

Yes PLEASE

Just did the same thing last night. Definitely need a WiFi only mode.

Accidrntally used up all my data a couple of times due to dropping wifi connection and not noticing. This setting would help to manage twitch data usage and prevent accidentally exceeding data caps.