WiFi has an event we listen for: https://github.com/mozilla/gaia-ui-tests/blob/master/gaiatest/atoms/gaia_data_layer.js#L166
Cell data uses an API property: https://github.com/mozilla/gaia-ui-tests/blob/master/gaiatest/atoms/gaia_data_layer.js#L304

You are using the API property `bluetooth.enabled` and therefore should be consistent with the `disableCellData` method. We should use `waitFor` and not `setInterval` and having this all on one line limits readability.