Well, back in the "early days" (a year or so ago

), things were a lot different.
the stock DJI blades were kinda crappy and we didn't really have good vibration isolation options (just "moon gel" or sorbe-thane), and you guys would cringe at what was considered decent Phantom video.
The guys getting the good stuff would be the ones who rose early (no winds), and flew with well balanced CF props.
But for everyone else, Jello was a headache we had to deal with.
But now we've got great brushless gimbal options, which are mounted on pretty good vibration isolation mounts - and DJI has improved their props considerably. Jello is no longer an issue. - and IMHO, that means CF props are no longer necessary.
it's still popular on the high end Octocopters and stuff, but putting them on a Phantom is simply overkill. (and dangerous).
As for prop guards, I'd say they definitely have their place.
let's face it, if you're a newbie, and you don't have the benefit of a huge open area, odds are really high you're doing to run into something. (or even into the ground). - and that usually means replacing a few props or more.
The prop guards are basically like having training wheels, and I'd say that they just might be better to have than not, at least for the first 10-20 flights.
Once once gets experience and confidence tho I say yank 'em and sell them to the next beginner. (or keep around if you think you'll be flying low amongst bushes and trees)