This strategy gonna win you are lot of games even at high level, but this strategy depends on your opponent not scouting, that's why I don't like it. Zerg in zvz should always have ovies around the base to see nydus incomming, the problem is most zerg never do that. Also it's 1 base nydus. If I see 1 base zerg with roaches and gonna make good amount of defense and try not to miss nydus.