I'm a little late on this, but I don't really understand the hostility towards the Super Guide. Do I personally care about it, no? Odds are good that I'll never see it. There aren't too many Mario games where I've died eight times in a row in the same level.
I personally appreciate it's inclusion, though, because I am one of those people who has a kid that will soon be old enough to begin playing games. And I can tell you that while kids are persistent, they can also get easily frustrated when they can't make something work the way they think it should. Mileage will vary, depending on their personality.
It does make me wonder why Nintendo chose eight lives as the magic number? Why not five? Why not ten? Did they perform tests or surveys on the frustration levels of various gamers?