4-4 high approach - why is the defensive approach prefered?
The main reason why I think you think this is good is because this joseki looks a lot like another familiar 3-4 joseki: http://josekipedia.com/#path:qdodocncpcndqfjd

$$ Good possibilities
$$ --------------|
$$ . . . . . . . |
$$ . . . . . . . |
$$ . X . X . . . |
$$ . . . , X . . |
$$ . . . O X . . |
$$ . a . O O . . |
$$ . . . . . . . |
$$ . . . c b . . |
$$ . . . . . . . |
$$ . . . O . . . |
$$ . . . . . . . |


But even though the difference between these two positions is only one line it cannot be overstated, black is good in that situation because he's closer to the corner, and it's secure, it's difficult to attack black.  Because black is solid, he doesn't have to worry about follow up moves and he has nice follow up moves of his own against white.  But in your right side variation, because it's one line farther out, there are too many weaknesses, black's corner is not secure.  So he can't necessarily count on the same follow up moves.

$$ Maybe not an option
$$ --------------|
$$ . . . . . . . |
$$ . . . . . . . |
$$ . . . . . . . |
$$ . X . X . . . |
$$ . . . . X . . |
$$ . . . O X . . |
$$ . ? . O O . . |
$$ . . . . . . . |
$$ . . . ? ? . . |
$$ . . . . . . . |
$$ . . . O . . . |
$$ . . . . . . . |


So it's becomes a trade, you're getting a little more corner "territory" for massive weakspots in that territory.  Later on white can even make an approach at the 8-3 point on the other side.  Black would normally want to pincer such a close approach, but cannot because the aji in the corner would become a big problem.  Black would need to play defensively, so white gets a free move, and black becomes overconcentrated and inefficient.  But it's either that or lose the corner, but if you were planning on giving up the corner then other moves would have been better suited.

As you can see from the given diagrams, black gets a large chunk of the side on the left as well and is difficult to attack.  On the right he's got a few more points in the corner, but because of the bad aji, he can't expect to get the side as well.  Even if he already has a stone at the 10-3 or 10-4, white has enough potential here to invade or reduce easily given the correct whole board situation.  There's not really an upside.  On the other hand, white's shape is ideal in the right side variation.

$$ The stuff of nightmares
$$ ----------------------|
$$ . . . . . . . . . . . |
$$ . . . . . . a c . . . |
$$ . X . O . . e . d . . |
$$ . , . . . X . X . . . |
$$ . . . b . . . . X . . |
$$ . . . . . . . O X . . |
$$ . . . . . . . O O . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . . . . . |
$$ . . . . . . . O . . . |
$$ . . . . . . . . . . . |


You pointed out the monkey jump.  Generally, monkey jumps are 10-point sente moves. (But that, of course, depends on the exact situation.)  Because it's normally sente for black, but gote for white, black is almost certainly going to get that move.  Those 10 points are 10 points you can count on if you're playing endgame correctly, because it's bigger for you to play it than your opponent.  If your opponent does get it that either means that you made a mistake and didn't play it early enough, or your opponent did and there's still larger points on the board.  So you can count on those 10 points.