How much weight can you squat?
I think there are 2 things of value that can be derived from practicing paused squats. The first is core stability throughout the rep. If you're having trouble with collapsing, or keeping your back rigid, then long paused squats like what you're doing seem like a good idea. They can also help with grooving the bottom position, particularly if depth is an issue.
I think shorter pauses should be implemented if the goal is to work on strength out of the hole (avoiding the use of the stretch reflex, or rebound). A 1 to 2 second pause should be sufficient if that is your aim.