Last question first - I feel no obligation to use everything from every book (even my teachers didn't completely)... but of course while always keeping in mind, that (particularly early on) we're not always fully aware of what we may or may not need.
So on the topic of things that are odd...
I've always very broken this subject into two subjects - that certainly overlap a lot, but are in my experience really quite different.
In your post, you mention "odd time signature sub-divisions" and also "quintuplets, septuplets, etc. In my book, these are two very different things....
Remember that grid that most of us were shown when we first started to learn to read.... that shows whole, half, quarter, eighth and 16th notes all laid out against each other - and how the smallest grid columns lined up with each of them. 1 e & ah 2 e & ah etc...
Then later when we learned about triplets, we realized that they exist primarily on a DIFFERENT grid - where the wholes, halves and quarters line up - but everything that divides the main 1/4 pulse is different.
Well learning "tuplets" is about adding more, uniquely different grids... one based on 5 notes per 1/2, another based on 7 per 1/4. And of course just like when we learned to play "3 against 2" (laying the triplet grid over the straight 1/8th grid ) - studying tuplets can become about superimposing them as well.
But basically, tuplets are about creating more grids that all share the same 1/4 note reference point. - layering more and more grids vertically (on top of each other)
On the other hand - odd time signatures and odd rhythm groups is all about using the existing basic grids (straight and triplet) and messing with the horizontal layout of the grid.... Instead of sixteen 16th notes per bar, we might have 20 (5/4) or fourteen 16ths (7/8). If in 7/8 (fourteen 16th's), the music might be arranged as two beats (1/4's) each having four 16th's followed by a "beat" with six 16th's (a dotted 1/8th beat) or the music might be arranged with the dotted 1/4 first, then the two 1/4's.
These odd time signature subdivisions and notice I keep referring to the music being divided as certain way. This is because just in 4/4 - the musician's don't really choose what subdivision to use - the music does (or the person writing the music does). A piece in 11/8 decided 3+3+3+2 is IN the sub-division, just as nearly all of rock in 4/4 is divided 2+2+2+2. These subdivisions don't really dictate what we play - they define where we should "tap our foot".
The other part of this is "odd rhythmic groupings" - most of get pretty efficient at creating rhythmic phrases in 4/4 made up of little groups of three - the BoDiddly Beat has some in it. Sing Sing Sing has some. They are so commonplace many of us don't even realize that is what we are doing. Playing strings of 16th's in "groups" of three - not triplets, but 16ths. Usually accented the first note of each group.
All that "odd rhythmic groupings" are is creating phrase, patterns, fills based on groupings beyond threes. It is just a way of opening up our rhythmic palette - within the context of 1/8th's, triplets and 16th's.
So two different things - in my career, being versed in odd time signatures and odd rhythmic groupings has been essential. Essential for everyone, of course not. Odd meter playing is still, 50 years later, in no way commonplace. But... it is (at the pro level) a skill that is far less "out there" than it was when I started. Is it the first and most important thing to master... heavens no. But it does come up.
As for tuplets - as drum set player, even one known to be very versed in odd meter playing, I have to say, they just don't come up that much. I believe this is in part that they are really a product of 20th century classical music and as such, traditionally, don't really "groove". Which even in odd music, is still our main function... to groove.
But... that is changing - in that this new generation of players have found these tuplet groove concepts that marvelously imitated the sort-of laid back, drunken grooves that developed on many rap records.
So I'm by know means saying ignore learning anything about tuplets - of course not. Just saying that even in the narrow world of more odd music being able to fully use those tuplet concepts like Vinnie can in his soloing is a skill - that while utterly amazing, is in very little demand. (I mean, Vinnie is in demand - but for a myriad of reasons that have nothing to do with the special unique ability)
Hope that helps...