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Imo winning a regional is more impressive but its also more luck based. Like if you get haxed out on battlespot you can still keep trying and after a specific amount of battles your rating will show your "real" skill. At regionals its much more about getting good matchups, having the right meta...
Its sometimes used in Pledge teams together with Primanera as their effect works like Tailwind. However, those teams are pretty matchup-based and out of them its not used at all