The current behavior is to disable navpops if hovercards are enabled, but navpops are the preferred tool of many editors and have features that are essential to their workflows. The reverse behavior should be true.
If I, as an editor, enable navpops, my hovercards should be disabled.
In the future, when we have finalized hovercards preferences, we will need a message explaining "hovercards cannot be enabled while navpops gadget is turned on"
This ticket reverses the behavior of: https://phabricator.wikimedia.org/T64952