The application "Conversations" doesn't alter availability status by default and regards it as an "expert setting" when other clients have it as a default.
Being aware of a contacts's availability is crucial when devices are always connected, everyone appearing ready to chat. The first 'P' in XMPP (Protocol name) is for Presence. Perhaps it was chosen to protect privacy, but both privacy and utility are possible.
1. Open "Settings" from main screen menu 2. Scroll to bottom and select "Expert settings" 3. Scroll down to "Availability" A. Untick "Manage availability manually" B. Tick "Away when screen is off"
To hide status, either don't add them to your contacts (it's still posible to message), or add them and disable "presence updates". This is done in a contact's details by untickicking "Send presence updates".