Unfortunately, the purpose of point attachments is different, as said on the Point Attachments - Spine User Guide page:

It can be used to spawn particles or do anything else that involves a position and/or rotation.

So they're just to mark places to spawn particles/effects/other skeletons/sprites for the programmers.

The method you're using is already a good one, but we've also considered implementing something as you suggested, unfortunately it's a bit hard to get down to a clear and feasable workflow. So if you have practical examples of how this should be done, feel free to suggest them (:

I'm not entirely sure I understand what you're after. But instead of trying to do this with parenting, you could maybe use Transform Constraints. At runtime, when you enable a skin, you could set the Mix to 100% on the correct Transform Constraints.

I used a similar approach in the Spineboy-pro example project. When you select the hoverboard animation, his feet will be placed on the board.

@Shiu utkiupe is trying to reuse the same animations on skins with different proportions of the body.
If a head is bigger, or feet are smaller, they can store in a one frame animation the new correct configuration of the bones and mix it at runtime to get the correct one.
When they say parent bones, they don't mean to reparent said bones, but to scale the parent bones to affect the children and obtain the new proportions they're after.
I think this workflow is definitely good, as Nate suggested this in another thread: can spine 'remember' image compensation per skin

The problem appears to be that some walks become unusable because the scaled IK behave according to the old proportions. I would have to try it, but maybe creating a bone that holds the IK (not the root of course), place it around the same height of the parent bones of the legs, parent the IKs to it (since they're not parented to the legs normally) then in the configuration animation they can scale the newly created bone so that the IKs are proportioned to the new size of the legs and their distance from the ground.

If we're all talking hacks,
Animation retargeting (or at least loading duplicates of animations to be compatible with a different skeleton) could be done at runtime. But the animator would have no way of checking and fixing the skeleton to ensure the resulting animations are correct. So that sucks. But handy if the style is very forgiving in terms of joint movements.

utkiupe. Your solution using meta bones sounds like an efficient workaround for the time being, though it would still be a bit if extra work to preview it in Spine. At least it's possible.
At runtime, you wouldn't need to keep the reconfiguration animations playing. As long as nothing else keys those bones, you'd only need to apply the animation once.

In my example above, the different proportions would be achieved by moving/scaling/rotating by using transform constraints.