The Church is pretty but there are SO many people in this plaza. Hard to get good pictures and the church was closed when we were there. I'd just make it a walk by stop, nothing you need to make a lot of time for.
Unfortunately, this church has been de-commissioned as have others in Cuba due to a radical decline in members but it is now a museum and is definately worth the visit. A climb to the bell tower provides glorious views of the city.