No personal experience but I would think it is just another tuning variable. If you have reason to believe that distribution issues aren't providing the A/F mixture to achieve best power for all cylinders then staggered jetting may be a way to correct that condition. Intake manifold porting to balance runner flow is another.
I know Holley's came with staggered jetting from the OEM's on certain applications. Not sure about Q jets. Perhaps someone more knowledgeable will chime in.
