Hi @lighteye. I believe steempeak uses steemconnect. In order to use steemconnect you need to provide your active key. The app doesn't see your active key but steemconnect uses it to allow the app to make a post.
Other apps may only require you to enter a posting key but they manage the security of keeping your posting key private.
I am aware that SteemPeak uses SteemConnect, @eroche. My question was WHY. Why SteemPeak can’t have at least an option of logging with posting key? Busy could do it in its first version.