Well, when it comes to rigging, where are many ways to skin a cat.

As usual, it depends...

Clothing merchants usually hate JCMs because they are an added complication when transferring a rig from a figure into a piece of clothing. And unless the clothing is really skin tight, you can't just auto-transfer a JCM with a single mouseclick, but you rather have to create a new one for the clothing item that corresponds with the one used in the figure.

So, avoiding them as much as possible is just best practise in rigging.

But yes, JCMs can easily do things no other method can do, so if I need extra realistic joint deformation for a nude shot, I just make a JCM and be done with it.

Now, the thing is: Proper bulge maps can go a long way to make a figure bend realistic (Or at least realistic enough for most Poser uses), but....Bulge maps aren't "Industry standard".

So Genesis 3 now is rigged without bulge maps, but uses lots of JCMs instead. (At least what's what I read in the DAZ forums)

How well that works with cloth rigging you have to ask some DAZ merchants.

Personally I like to rig a figure as best as I can without JCMs and only use when I am getting tired of strugling with a few vertices that refuse to behave properly.

This usually results in the most "stable" and less resource hungry rig.

I don't like "ghost bones" or similar, because I pose my figures manually and additional bodyparts make it harder to select the bodypart I want to move with the mouse.

But as I said, many ways to skin a cat.

With one or two dozend JCMs I could probably make Posette bend as well as Vicky 7 without actual weightmapping while keeping her perhaps at least Poser 6 compatible. Lol.