If we had a few more option over when and where they're displayed this would really improve their usefulness.
At the moment we have to check the "Show on the Main Collections Page" for children to show in a parent collection. So to be able to use Parent/Child feature everything must show on the collections page.
I'd like to start using collections more in the nav, but this sort of collection is less useful on the collections page which could be reserved for a curated information based collections. Having less would be easier to find from within the site.
Even if we just have the ability to hide the child collections from the collection page would be a great help as we could house all the care related child collection under the broader why care is good parent.