Yeah, what I say, is check out the Hybrid Rudiment thing on Vic Firth website. Casey Brohard talks about them, and what he says makes sense, although you might disagree with it. I mean he demonstrates ridiculous grace note control and its insane. So I mean if you wanna do that? I would practice them... But I would just kinda practice grace note placement as a whole and not just malfs, ya know? So you can possibly do what he does. Actually I spent this whole time talking bout it, so I just went and got a link. OK here goes.
http://vicfirth.com/education/hybrids/malf.html
alright check it out.

Some previous players mentioned Africa Hot (John Wooton's solo from Row-Loff Productions), which does contain malfs. Africa Hot does several interesting things with flams, forcing performers to have exceptional control over every aspect of a flam (grace note positioning, fake primary stroke, etc.). The coolest flam-based thing that the solo does is applies the malf to the paradiddle, which opens so many doors. You can apply malfs to any rudiment/ hybrid with flams by simply replacing them. For a real challenge try playing a rudiment/ hybrid with multiple flams, replacing some (but not all) with malfs; this leaves you having to be able to shift your grace note positioning while playing (without stopping to regroup).

To answer the original question, no, malfs aren't "necessary." However if you plan to take a swing at Africa Hot, you will need them. Malfs are designed to improve control over grace notes, which in turn improves your overall stick control. If you are ok with being a decent drummer (not a good or great one), you may be able to skip these, but there are people who can use/ apply them and just like any rudiment, however rare it may be, you may encounter it at some point (in music or most likely in an audition) and you may wish you had taken the time to learn it.

If you look up "Great drummer" in a dictionary, does it say "One who has a mastery of stick control, rhythms and malfs?
I don't believe so.

I don't remember when the last time I heard Steve Gadd play a malf was, either...

I am NOT trying to be rude, just to clarify what I said.

A. I doubt that there is a definition in any dictionary, anywhere for "great drummer," but I (personally) would group malfs under the "Stick Control" aspect that you mentioned (as I tried to convey in my original post). I don't believe that malfs are necessary, but the skills they help build are quite valuable. (my main idea) Additionally, malfs aren't practical for performance unless you are just showing off your bag of tricks, however, (like I have mentioned) it is the skills you gain from using them in practice that improve your playing within a line (where grace note spacing and control is most important) or in a solo when it comes time for a performance.

B. Steve Gadd, being a drumset player (not a rudimental, marching line player), probably doesn't use malfs much because they have little value to drumset players in performance (but, like all rudiments, still do have some value when it comes to the set). Also, he probably doesn't use them in performance because they are impractical, and if he does it would be a challenge to tell one from a regular flam in the context of playing behind a full kit. However, I would imagine he could play them if asked OR would not have a hard time learning them.

Hope this makes my original post more clear.

/thread.