Objective of SMB Warp Zones?
Historically, the majority of Mario video games have some means to bypass huge areas of the video game (Warp Zones in SMB1, Warp Whistles in SMB3, Star World in SMW) along with powerups that permit you to miss specific degrees (raccoon tail, cape). Miyamoto's ideology is that you should not get stuck attempting to surpass a degree if you do not intend to.
Generally when debugging a video game under growth, a designer places in numerous means to miss in advance to later degrees (such as key combinations) that do not constantly make it right into the last launched item. This suggests warp areas were possibly except screening objectives.
I believe they were simply enjoyable and also intriguing keys.